Maybe another apostrophe is missing too (7)
I believe the answer is:
perhaps
'maybe' is the definition.
(synonyms)
'another apostrophe is missing too' is the wordplay.
'another' is an anagram indicator.
'is missing' suggests deleting specific letters.
'apostrophe' with 'too' removed is 'apsrphe'.
'apsrphe' with letters rearranged gives 'PERHAPS'.
(Other definitions for perhaps that I've seen before include "Could be, maybe" , "Possibly, maybe" , "It may be" , "Not necessarily" , "say" .)