Perceive intelligence shown by head (7)
I believe the answer is:
witness
'perceive' is the definition.
(thesaurus)
'intelligence shown by head' is the wordplay.
'intelligence' becomes 'wit' (wit is a kind of intelligence).
'shown by' means one lot of letters go next to another.
'head' becomes 'ness' (type of geographical point).
'wit'+'ness'='WITNESS'
(Other definitions for witness that I've seen before include "One giving evidence" , "Spectator" , "Evidence, proof" , "One who saw an event, may give evidence" , "Court testifier" .)