Used other than figuratively or idiomatically: see let, down.
To allow to descend.
They let down the rope and I fastened it to the basket.
To disappoint; to betray or fail somebody.
I promised him I would meet him there, and I will not let him down.
To lengthen by undoing and resewing a hem.
To reduce one's level of effort.
To soften in tempering.
to let down tools or cutlery
To thin; to reduce the thickness or viscosity of.
let the sauce down with a little pasta water if it starts to become too thick; if the soup is too thick, you can let it down with a little milk; let the sauce down with a dash of the pickling liquor; use some of the stock to let down the onion sauce