Runs to escape bad-tempered elk (5)
I believe the answer is:
moose
'elk' is the definition.
(I know that elk can be written as moose)
'runs to escape bad-tempered' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'to escape' indicates named letters should be taken away.
'bad-tempered' becomes 'morose' (morose means sad or in a bad mood).
'morose' with 'r' removed is 'MOOSE'.
(Other definitions for moose that I've seen before include "Large northern deer" , "Ungulate" , "beasts" , "Large N American deer like European elk" , "North American deer" .)