Reserved ABAP keywords

Sometime it is little bit tricky to find out a name for new variable in ABAP until you do not break into a set of reserved ABAP keyword. Basically such a set of reserved words are all the ABAP statements key words, logical operators, data types, predefined functions, etc. According official SAP documentation (see TA ABAPDOCU -> ABAP - By Theme -> ABAP syntax -> ABAP Statements ->ABAP Words) usage of those key words is not forbidden (see picture) we should try avoiding using them. It might happen that there will be some new key words added and your code will not be compatible with further new version of SAP ABAP/Basis/WAS component. 

Therefore while you designing new variable names consider following names as those which are forbidden and you cannot use them as variable names:

ABAP-SOURCE	ABBREVIATED	ABS	ABSTRACT	ACCEPT
ACCEPTING	ACCORDING	ACOS	ACTIVATION	ACTUAL
ADD	ADD-CORRESPONDING	ADJACENT	AFTER	ALIASES
ALL	ALLOCATE	ANALYSIS	ANALYZER	AND
ANY	APPEND	APPENDAGE	APPENDING	APPLICATION
ARCHIVE	AREA	ARITHMETIC	AS	ASCENDING
ASIN	ASSERT	ASSIGN	ASSIGNED	ASSIGNING
AT	ATAN	ATTRIBUTES	AUTHORITY	AUTHORITY-CHECK
AVG	BACK	BACKGROUND	BACKUP	BACKWARD
BADI	BEFORE	BEGIN	BETWEEN	BIG
BINARY	BIT	BIT-AND	BIT-NOT	BIT-OR
BIT-XOR	BLACK	BLANK	BLANKS	BLOCK
BLOCKS	BLUE	BOUND	BOUNDARIES	BOUNDS
BREAK-POINT	BT	BUFFER	BY	BYPASSING
BYTE	BYTE-CA	BYTE-CN	BYTE-CO	BYTE-CS
BYTE-NA	BYTE-NS	BYTE-ORDER	C	CA
CALL	CALLING	CASE	CASTING	CATCH
CEIL	CENTERED	CHAIN	CHAIN-INPUT	CHAIN-REQUEST
CHANGE	CHANGING	CHAR-TO-HEX	CHARACTER	CHARLEN
CHECK	CHECKBOX	CIRCULAR	CLASS	CLASS-CODING
CLASS-DATA	CLASS-EVENTS	CLASS-METHODS	CLASS-POOL	CLEANUP
CLEAR	CLIENT	CLIKE	CLOCK	CLOSE
CN	CO	CODE	CODEPAGE	CODING
COL_BACKGROUND	COL_GROUP	COL_HEADING	COL_KEY	COL_NEGATIVE
COL_NORMAL	COL_POSITIVE	COL_TOTAL	COLLECT	COLOR
COLUMN	COMMENT	COMMENTS	COMMIT	COMMON
COMMUNICATION	COMPARING	COMPONENT	COMPONENTS	COMPRESSION
COMPUTE	CONCATENATE	CONDENSE	CONDITION	CONNECT
CONNECTION	CONSTANTS	CONTEXT	CONTEXTS	CONTINUE
CONTROL	CONTROLS	CONVERSION	CONVERT	COPIES
COPY	CORRESPONDING	COS	COSH	COUNT
COUNTRY	COVER	CP	CPI	CREATE
CS	CSEQUENCE	CURRENCY	CURRENT	CURSOR
CURSOR-SELECTION	CUSTOMER-FUNCTION	D	DATA	DATABASE
DATAINFO	DATASET	DATE	DAYLIGHT	DBMAXLEN
DD/MM/YY	DD/MM/YYYY	DDMMYY	DEALLOCATE	DECIMALS
DEFAULT	DEFERRED	DEFINE	DEFINING	DEFINITION
DELETE	DELETING	DEMAND	DEPARTMENT	DESCENDING
DESCRIBE	DESTINATION	DETAIL	DIALOG	DIRECTORY
DISCONNECT	DISPLAY	DISPLAY-MODE	DISTANCE	DISTINCT
DIV	DIVIDE	DIVIDE-CORRESPONDING	DO	DUMMY
DUPLICATE	DUPLICATES	DURING	DYNAMIC	DYNPRO
E	EDIT	EDITOR-CALL	ELSE	ELSEIF
ENABLED	ENABLING	ENCODING	END	END-ENHANCEMENT-SECTION
END-LINES	END-OF-DEFINITION	END-OF-FILE	END-OF-PAGE	END-OF-SELECTION
ENDAT	ENDCASE	ENDCATCH	ENDCHAIN	ENDCLASS
ENDDO	ENDENHANCEMENT	ENDEXEC	ENDFORM	ENDFUNCTION
ENDIAN	ENDIF	ENDING	ENDINTERFACE	ENDLOOP
ENDMETHOD	ENDMODULE	ENDON	ENDPROVIDE	ENDSELECT
ENDTRY	ENDWHILE	ENHANCEMENT	ENHANCEMENT-POINT	ENHANCEMENT-SECTION
ENHANCEMENTS	ENTRIES	ENTRY	ENVIRONMENT	EQ
ERRORMESSAGE	ERRORS	ESCAPE	ESCAPING	EVENT
EVENTS	EXCEPTION	EXCEPTION-TABLE	EXCEPTIONS	EXCLUDE
EXCLUDING	EXEC	EXECUTE	EXISTS	EXIT
EXIT-COMMAND	EXP	EXPAND	EXPIRATION	EXPLICIT
EXPONENT	EXPORT	EXPORTING	EXTENDED	EXTENSION
EXTRACT	F	FETCH	FIELD	FIELD-GROUPS
FIELD-SYMBOLS	FIELDS	FILE	FILTER	FILTERS
FINAL	FIND	FIRST	FIRST-LINE	FIXED-POINT
FKEQ	FKGE	FLOOR	FLUSH	FONT
FOR	FORM	FORMAT	FORWARD	FOUND
FRAC	FRAME	FRAMES	FREE	FRIENDS
FROM	FTO	FUNCTION	FUNCTION-POOL	GAPS
GE	GENERATE	GET	GIVING	GKEQ
GKGE	GLOBAL	GREEN	GROUP	GROUPS
GT	HANDLE	HANDLER	HASHED	HAVING
HEAD-LINES	HEADER	HEADERS	HEADING	HELP-ID
HELP-REQUEST	HIDE	HIGH	HINT	HOLD
HOTSPOT	I	ICON	ID	IDENTIFICATION
IDENTIFIER	IDS	IF	IGNORING	IMMEDIATELY
IMPLEMENTATION	IMPLEMENTATIONS	IMPORT	IMPORTING	IN
INCLUDE	INCLUDES	INCLUDING	INCREMENT	INDEX
INDEX-LINE	INFOTYPES	INHERITING	INIT	INITIAL
INITIALIZATION	INNER	INOUT	INPUT	INSERT
INSTANCES	INTENSIFIED	INTERFACE	INTERFACE-POOL	INTERFACES
INTERNAL	INTERVALS	INTO	INVERSE	INVERTED-DATE
IS	JOB	JOIN	KEEP	KEEPING
KERNEL	KEY	KEYS	KEYWORDS	KIND
LANGUAGE	LAST	LATE	LAYOUT	LE
LEADING	LEAVE	LEFT	LEFT-JUSTIFIED	LEGACY
LENGTH	LEVEL	LEVELS	LIKE	LINE
LINE-COUNT	LINE-SELECTION	LINE-SIZE	LINEFEED	LINES
LIST	LIST-PROCESSING	LISTBOX	LITTLE	LOAD
LOAD-OF-PROGRAM	LOCAL	LOCALE	LOG	LOG-POINT
LOG10	LOGFILE	LOOP	LOW	LOWER
LPI	LT	M	MAIL	MAIN
MAJOR-ID	MARGIN	MARK	MASK	MATCH
MATCHCODE	MAX	MAXIMUM	MEMORY	MESSAGE
MESSAGE-ID	MESSAGES	METHOD	METHODS	MIN
MINIMUM	MINOR-ID	MM/DD/YY	MM/DD/YYYY	MMDDYY
MOD	MODE	MODIF	MODIFIER	MODIFY
MODULE	MOVE	MOVE-CORRESPONDING	MULTIPLY	MULTIPLY-CORRESPONDING
N	NA	NAME	NAMETAB	NATIVE
NB	NE	NESTING	NEW	NEW-LINE
NEW-PAGE	NEW-SECTION	NEXT	NO	NO-DISPLAY
NO-EXTENSION	NO-EXTENSIONS	NO-GAP	NO-GAPS	NO-GROUPING
NO-HEADING	NO-SCROLLING	NO-SIGN	NO-TITLE	NO-TOPOFPAGE
NO-ZERO	NODE	NODES	NON-UNICODE	NON-UNIQUE
NOT	NP	NS	NULL	NUMBER
NUMERIC	NUMOFCHAR	O	OBJECT	OBJECTS
OBLIGATORY	OCCURRENCE	OCCURRENCES	OCCURS	OF
OFF	OFFSET	OLE	ON	ONLY
OPEN	OPTION	OPTIONAL	OPTIONS	OR
ORDER	OTHERS	OUT	OUTER	OUTPUT
OUTPUT-LENGTH	OVERFLOW	OVERLAY	P	PACK
PACKAGE	PADDING	PAGE	PAGES	PARAMETER
PARAMETER-TABLE	PARAMETERS	PART	PATTERN	PERCENTAGE
PERFORM	PERFORMING	PERSON	PF	PF-STATUS
PINK	PLACES	POOL	POSITION	PRECOMPILED
PREFERRED	PRESERVING	PRIMARY	PRINT	PRINT-CONTROL
PRIORITY	PRIVATE	PROCEDURE	PROCESS	PROGRAM
PROPERTY	PROTECTED	PROVIDE	PUBLIC	PUSHBUTTON
PUT	QUEUE-ONLY	QUICKINFO	RADIOBUTTON	RAISE
RAISING	RANGE	RANGES	READ	READ-ONLY
RECEIVE	RECEIVED	RECEIVER	RECEIVING	RED
REDEFINITION	REF	REFERENCE	REFRESH	REGEX
REJECT	RENAMING	REPLACE	REPLACEMENT	REPLACING
REPORT	REQUEST	REQUESTED	RESERVE	RESET
RESOLUTION	RESPECTING	RESPONSIBLE	RESULT	RESULTS
RETURN	RETURNCODE	RETURNING	RFC	RIGHT
RIGHT-JUSTIFIED	ROLLBACK	ROUND	ROWS	RUN
SAP	SAP-SPOOL	SAVING	SCAN	SCREEN
SCROLL	SCROLL-BOUNDARY	SCROLLING	SEARCH	SECONDS
SECTION	SELECT	SELECT-OPTIONS	SELECTION	SELECTION-SCREEN
SELECTION-SET	SELECTION-SETS	SELECTION-TABLE	SELECTIONS	SEND
SEPARATE	SEPARATED	SET	SHARED	SHIFT
SHORTDUMP-ID	SIGN	SIMPLE	SIN	SINGLE
SINH	SIZE	SKIP	SKIPPING	SMART
SOME	SORT	SORTABLE	SORTED	SOURCE
SPECIFIED	SPLIT	SPOOL	SPOTS	SQL
SQRT	STABLE	STAMP	STANDARD	START-OF-SELECTION
STARTING	STATE	STATEMENT	STATEMENTS	STATIC
STATICS	STATUSINFO	STEP-LOOP	STOP	STRING
STRLEN	STRUCTURE	STRUCTURES	SUBKEY	SUBMATCHES
SUBMIT	SUBROUTINE	SUBSCREEN	SUBSTRING	SUBTRACT
SUBTRACT-CORRESPONDING	SUFFIX	SUM	SUMMARY	SUMMING
SUPPLIED	SUPPLY	SUPPRESS	SWITCH	SWITCHSTATES
SYMBOL	SYNCPOINTS	SYNTAX-CHECK	SYNTAX-TRACE	SYSTEM-CALL
SYSTEM-EXCEPTIONS	SYSTEM-EXIT	T	TAB	TABBED
TABLE	TABLES	TABLEVIEW	TABSTRIP	TAN
TANH	TASK	TEST	TESTING	TEXT
TEXTPOOL	THEN	TIME	TIMES	TITLE
TITLE-LINES	TITLEBAR	TO	TOKENIZATION	TOKENS
TOP-LINES	TOP-OF-PAGE	TRACE-FILE	TRACE-TABLE	TRAILING
TRANSACTION	TRANSFER	TRANSFORMATION	TRANSLATE	TRANSPORTING
TRMAC	TRUNC	TRUNCATE	TRUNCATION	TRY
TYPE	TYPE-POOL	TYPE-POOLS	TYPES	ULINE
UNASSIGN	UNDER	UNICODE	UNIQUE	UNIT
UNIX	UNPACK	UNTIL	UP	UPDATE
UPPER	USER	USER-COMMAND	USING	UTF-8
VALID	VALUE	VALUE-REQUEST	VALUES	VARY
VARYING	VERIFICATION-MESSAGE	VERSION	VIA	VISIBLE
WAIT	WARNING	WHEN	WHENEVER	WHERE
WHILE	WIDTH	WINDOW	WINDOWS	WITH
WITH-HEADING	WITH-TITLE	WITHOUT	WORD	WORK
WRITE	X	XML	XSEQUENCE	XSTRING
XSTRLEN	YELLOW	YYMMDD	Z	ZONE