Angry buccaneer loses head (5)
I believe the answer is:
irate
'angry' is the definition.
(irate can mean angry or annoyed)
'buccaneer loses head' is the wordplay.
'buccaneer' becomes 'pirate' (historical term for a pirate).
'loses head' means to remove the first letter.
'pirate' with its initial letter taken away is 'IRATE'.
(Other definitions for irate that I've seen before include "Mad" , "Not happy" , "Narked" , "Spitting feathers" , "raging" .)