Don't try so much, it's vulgar! (9)
I believe the answer is:
tasteless
'vulgar' is the definition.
(similar in meaning)
'don't try so much it's' is the wordplay.
I cannot really see how this works, but
'try' could be 'taste' (synonyms) and 'taste' is found in the answer.
'it's' could be 'es' ('e' can mean 'electronic' which is similar to 'IT') and 'es' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tasteless that I've seen before include "Unseemly" , "Bland; offensive" , "Lacking flavour or ability to appreciate the beautiful" , "Lacking in aesthetic judgement" , "Lacking flavour or aesthetic appreciation" .)