Has entered winter content hurriedly (2,5)
I believe the answer is:
in haste
'hurriedly' is the definition.
(synonyms)
'has entered winter content' is the wordplay.
'entered' means one lot of letters goes inside another.
'content' means to look at the middle letters.
The central letters of 'winter' are 'inte'.
'has' put within 'inte' is 'IN HASTE'.
(Other definitions for in haste that I've seen before include "Rashly (how not to marry?)" , "Quickly" , "Rushing round" , "Rapidly" , "Hurriedly" .)