(intransitive, or transitive with of) To have an insufficient amount (of).
To sell a financial product, such as a share, that one does not presently own, as in the hope of buying it more cheaply later for delivery, so as to profit from a fall in price; cf. go long.
To reduce one's level of effort.
To disappoint; to betray or fail somebody
To soften in tempering.
Used other than figuratively or idiomatically: see let, down.
To allow to descend.
To lengthen by undoing and resewing a hem.