Put up a lump of metal (6)
I believe the answer is:
billet
'put up' is the definition.
(thesaurus)
'a lump of metal' is the wordplay.
I cannot quite understand how this works, but
'metal' could be 'bi' (Bi is an example) and 'bi' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for billet that I've seen before include "Lodging for military personnel" , "Requisitioned accommodation" , "Lodgings for troops or evacuees" , "living quarters" , "Soldier's lodging" .)