Idiom: To let someone down;
used as a verb
Jeffrey was sure he could make the
goal, so he asked Thomas to kick him the ball. But he missed the goal and his
team lost. He really let them down.
Jenna promised her mom that they
would have breakfast together on Mother’s Day, but she forgot to set her alarm.
When she woke up at 11am, she called her
mom, but she had already had gone out for brunch with a friend. Jenna said she
was sorry that she let her mom down and promised to make up for it
Meaning: To “let someone
down” means to fail or disappoint that person or group. Usually, this
expression is used when the person/group being let down was relying on the person to be successful, and the
failure was that person’s fault. In the first example/illustration above, Jeffrey
missed after he said he was sure that he
could make the goal; if he hadn’t said he could make it, he wouldn’t have let them down. In the second example, Jenna let her mom down after
sleeping through the Mother’s Day breakfast she promised.