let down

verb
High School
1

To allow to descend.

2

To disappoint; to betray or fail somebody.

3

To lengthen by undoing and resewing a hem.

4

To reduce one's level of effort.

5

To soften in tempering.

6

To thin; to reduce the thickness or viscosity of.

7

Used other than figuratively or idiomatically: see let, down.