Relative in fleece instantly turned up (5)
I believe the answer is:
niece
'relative' is the definition.
(type of relative)
'in fleece instantly turned up' is the wordplay.
'in' indicates the answer is hidden within the clue.
'turned up' is a reversal indicator.
'ecein' is hidden within 'fleece instantly'.
'ecein' in reverse letter order is 'NIECE'.
(Other definitions for niece that I've seen before include "Female relation" , "A sibling's daughter" , "Brother or sister's daughter" , "Daughter of a sibling" , "Son's cousin" .)