Raised bar? This person's hard to pin down (7)
I believe the answer is:
evasive
'hard to pin down' is the definition.
(I've seen this in another clue)
'raised bar? this person's' is the wordplay.
'raised' is a reversal indicator (going up in a down clue).
'bar?' becomes 'save' (both can mean 'except').
'this person's' becomes 'I've' (as in 'this person has', 'I have').
'save' reversed gives 'evas'.
'evas'+'ive'='EVASIVE'
(Other definitions for evasive that I've seen before include "Shifty, dodging question" , "Avoiding commitment" , "Quibbling" , "Avoiding giving answers" , "Ambiguous" .)