Huge bird, one in charge (7)
I believe the answer is:
titanic
'huge' is the definition.
(thesaurus)
'bird one in charge' is the wordplay.
'bird' becomes 'tit' (I've seen this before).
'one' becomes 'an' (I've seen this in other clues).
'in charge' becomes 'ic'.
'tit'+'an'+'ic'='TITANIC'
(Other definitions for titanic that I've seen before include "Ship that sank in 1912" , "Iceberg-hitting ship" , "Film success (1997) - ship disaster (1912)" , "like Oceanus" , "Ill-fated vessel" .)