Dic: fail somebody

■

[Cobuild] If someone fails you, they do not do what you had expected or trusted them to do.

• ...communities who feel that the political system has failed them.

[OALD] DISAPPOINT SB: 6. [vn]

1. to disappoint sb;
2. to be unable to help when needed.

• When he lost his job, he felt he had failed his family.
• She tried to be brave, but her courage failed her.
• Words fail me (=I cannot express how I feel).

■ CF.
[Cobuild] If someone fails you in a test, examination, or course, they judge that you have not reached a high enough standard in it. (≠ pass)

• ...the two men who had failed him during his first year of law school.

[LDOCE] to decide that someone has not passed a test or examination

• 　Her work was so bad that I had no choice but to fail her.