Give me a certain dimension (7)
I believe the answer is:
measure
'dimension' is the definition.
(thesaurus)
'give me a certain' is the wordplay.
'give' is a charade indicator (letters next to each other).
'certain' becomes 'sure' (synonyms).
'me' put next to 'a' is 'mea'.
'mea'+'sure'='MEASURE'
(Other definitions for measure that I've seen before include "Take size of" , "Unit of verse" , "Shakespeare play: ''Measure for . . . . . . .''" , "Standard unit; dance" , "Calculate size" .)