Sense state is changing (5)
I believe the answer is:
taste
'sense' is the definition.
(taste is one of the five senses)
'state is changing' is the wordplay.
'is changing' indicates anagramming the letters.
'state' anagrammed gives 'TASTE'.
(Other definitions for taste that I've seen before include "Discrimination - a sense" , "Small sample of food" , "eat only the smallest amount" , "Sip" , "Sample, savour" .)