Tense setter is cutting short cigar (9)
I believe the answer is:
imperfect
'tense' is the definition.
(the imperfect tense is a grammatical tense)
'setter is cutting short cigar' is the wordplay.
'setter is' becomes 'I'm' (the setter is the person who set the crossword).
'cutting short' means to remove the last letter.
'cigar' becomes 'perfecto' (type of cigar).
'perfecto' with its last letter removed is 'perfect'.
'im'+'perfect'='IMPERFECT'
(Other definitions for imperfect that I've seen before include "Flawed, defective" , "Describing continuous actions" , "Faulty; tense" , "being immature" , "seconds" .)