Silk fabric cut completely from the bottom (8)
I believe the answer is:
prunella
'silk fabric' is the definition.
(I've seen this before)
'cut completely from the bottom' is the wordplay.
'cut' becomes 'prune' ('prune' can be a synonym of 'cut').
'completely' becomes 'all' ('all' can be a synonym of 'completely').
'from the bottom' is a reversal indicator.
'all' reversed gives 'lla'.
'prune'+'lla'='PRUNELLA'
(Other definitions for prunella that I've seen before include "It reputedly heals everyone" , "climbing plant" , "flower" , "-- Scales, actress" , "Strong silk" .)