Tryingly irritable (5)
I believe the answer is:
testy
'irritable' is the definition.
(testy can mean irritable or annoyed)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for testy that I've seen before include "Irascible" , "Cross" , "bad temper" , "Easily irritated" , "Short-tempered" .)