Angry sea bandit losing plot initially (5)
I believe the answer is:
irate
'angry' is the definition.
(similar in meaning)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for irate that I've seen before include "A tier (anag)" , "Extremely angry" , "Annoyed, irritated" , "Angry - furious" , "Annoyed, exasperated" .)