Irritated, flying three sheets to the wind (7)
I believe the answer is:
uptight
'irritated' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for uptight that I've seen before include "Showing repressed anxiety or anger" , "Repressed and disapproving" , "Like a tense person" , "Tense or angry" , "Tip thug, being nervously tense" .)