Second best hoot (6)
I believe the answer is:
scream
'hoot' is the definition.
(thesaurus)
'second best' is the wordplay.
'second' becomes 's' (common abbreviation).
'best' becomes 'cream' (I've seen this before).
's'+'cream'='SCREAM'
(Other definitions for scream that I've seen before include "Scar me (anag)" , "Person who seems extremely funny?" , "Sound terrified" , "Indication of terror - how funny!" , "A long piercing cry as of terror" .)