Lockandkey

3 clues
Door duo
Pair for a certain smith
Under ___ (securely shut in)
Similar answers:
Auctionblockage
Blockade
Blockader
Blockaderunners
Blockaderunning
Blockades
Blockage
Blockandlot
Blockandtackle
Blockarty
Blockashot
Chipofftheoldblockade
Clockandboasted
Lochandkey
Locka
Lockandkey
Lockandlad
Lockandload
Lockaway
Matlockandload