Cares about alarm (5)
I believe the answer is:
scare
'alarm' is the definition.
(I've seen this before)
'cares about' is the wordplay.
'about' is an anagram indicator.
'cares' is an anagram of 'SCARE'.
(Other definitions for scare that I've seen before include "Startle" , "Greatly frighten" , "Cause fright, alarm" , "Panic" , "Frighten or intimidate" .)