Feel gutted, less healthy, with no initial sign of life? (7)
I believe the answer is:
flicker
'sign of life?' is the definition.
(a flicker is a tiny movement)
'feel gutted less healthy with no initial' is the wordplay.
'gutted' suggests removing the centre (to gut something is to remove its insides).
'less healthy' becomes 'sicker' (more sick or unwell).
'with no initial' means to remove the first letter.
'feel' with its centre removed is 'fl'.
'sicker' with its initial letter taken off is 'icker'.
'fl'+'icker'='FLICKER'
(Other definitions for flicker that I've seen before include "Burn or shine unsteadily" , "Shine unsteadily; waver" , "Woodpecker" , "Vary rapidly in brightness" , "Glimmer" .)