Impatient? Try one of the axes (5)
I believe the answer is:
testy
'impatient?' is the definition.
(I've seen this in another clue)
'try one of the axes' is the wordplay.
'try' becomes 'test' (synonyms).
'one of the axes' becomes 'y' (I can't justify this - if you can you should give a lot more credence to this answer).
'test'+'y'='TESTY'
Can you help me to learn more?
(Other definitions for testy that I've seen before include "Easily annoyed" , "Showing irritation" , "snappy" , "Short-tempered" , "likely to flare up?" .)