Antonyms of verb unbolt

1 sense of unbolt

Sense 1
unbolt -- (undo the bolt of; "unbolt the door")
       Antonym of bolt (Sense 2)
      => bolt -- (secure or lock with a bolt; "bolt the door")

Synonyms/Hypernyms (Ordered by Estimated Frequency) of verb unbolt

1 sense of unbolt

Sense 1
unbolt -- (undo the bolt of; "unbolt the door")
       => open, open up -- (cause to open or to become open; "Mary opened the car door")

Antonyms of adj unbolted

1 sense of unbolted

Sense 1
unbarred, unbolted, unlatched, unlocked, unsecured -- (not firmly fastened or secured; "an unbarred door"; "went through the unlatched gate into the street"; "an unlocked room")

INDIRECT (VIA unfastened) -> fastened -- (firmly closed or secured; "found the gate fastened"; "a fastened seatbelt")

Similarity of adj unbolted

1 sense of unbolted

Sense 1
unbarred, unbolted, unlatched, unlocked, unsecured -- (not firmly fastened or secured; "an unbarred door"; "went through the unlatched gate into the street"; "an unlocked room")
       => unfastened (vs. fastened) -- (not closed or secured; "the car door was unfastened"; "unfastened seatbelts")