Camp it up to make an impression (6)
I believe the answer is:
impact
'an impression' is the definition.
(thesaurus)
'camp it up' is the wordplay.
'up' is an anagram indicator.
'camp'+'it'='campit'
'campit' is an anagram of 'IMPACT'.
'to make' acts as a link.
(Other definitions for impact that I've seen before include "Marked effect; hit" , "Serious effect" , "Repercussion" , "Forcible contact; marked influence" , "Bear upon" .)