Feelings time soon alters (8)
I believe the answer is:
emotions
'feelings' is the definition.
(I know this)
'time soon alters' is the wordplay.
'alters' indicates an anagram.
'time'+'soon'='timesoon'
'timesoon' with letters rearranged gives 'EMOTIONS'.
(Other definitions for emotions that I've seen before include "Intense mental feelings, like love or hate" , "instinctive feelings" , "Feelings provoked by noise, Tom" , "Passions" , "Strong feelings" .)