Peevish due to a trying time (5)
I believe the answer is:
testy
'peevish' is the definition.
(synonyms)
'a trying time' is the wordplay.
I cannot quite see how this works, but
'time' could be 'est' (EST is an example) and 'est' is found in the answer.
This explanation may well be incorrect...
'due to' acts as a link.
Can you help me to learn more?
(Other definitions for testy that I've seen before include "Short-tempered" , "Bad-tempered" , "Captious" , "Easily irritated" , "snappy" .)