Rivet (7)
'rivet' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for bolt that I've seen before include "Crossbow missile" , "It makes fast" , "eat food quickly and > lock up" , "Runner" , "Escape" .)
'rivet' is the definition.
(engrossing is a kind of riveting)
This is all the clue.
(Other definitions for engross that I've seen before include "Rivet" , "grab attention" , "Absorb, captivate" , "Engulf" , "Absorb the attention of (someone)" .)