Contrive to hold a bolt (5)
I believe the answer is:
rivet
'a bolt' is the definition.
(I've seen this before)
'contrive to hold' is the wordplay.
'hold' indicates the answer is hidden within the clue (I've seen 'holding' mean this).
'RIVET' is hidden in the letters of 'contrive to'.
(Other definitions for rivet that I've seen before include "Fasten -- engross" , "Clinch - bolt" , "Type of fastening" , "make fast" , "Engross attention" .)