- Used other than as an idiom: see let, down.
- (transitive) To allow to descend.
- They let down the rope and I fastened it to the basket.
- (transitive, idiomatic) To disappoint; to betray or fail somebody
- I promised him I would meet him there, and I will not let him down.
- (transitive, of clothing) To lengthen by undoing and resewing a hem.
- (intransitive) To reduce one's level of effort.
- To soften in tempering.
- to let down tools or cutlery
to allow to descend