Bond part involves hell, occasionally (8)
I believe the answer is:
relation
'bond' is the definition.
(thesaurus)
'part involves hell occasionally' is the wordplay.
'part' becomes 'ration' (ration is a kind of part**).
'involves' means one lot of letters goes inside another.
'occasionally' indicates alternate letters.
The alternate letters of 'hell' are 'el'.
'ration' enclosing 'el' is 'RELATION'.
(Other definitions for relation that I've seen before include "wife?" , "Kinsman or kinswoman" , "Person related by blood or marriage" , "Respect" , "Eg, father" .)