sell short
sell (someone/something) short
to not appreciate the qualities of someone or something as much as they deserve.
I think her presentation really sold Morocco short.

Usage notes: sometimes used in the form sell yourself short - not have reasonable confidence in your abilities:
She doesn't succeed in interviews because she always sells herself short.

[TahlilGaran] English Idioms Dictionary ▲

sell something short
sell (someone/something) short
to not appreciate the qualities of someone or something as much as they deserve.
I think her presentation really sold Morocco short.

Usage notes: sometimes used in the form sell yourself short - not have reasonable confidence in your abilities:
She doesn't succeed in interviews because she always sells herself short.

[TahlilGaran] English Idioms Dictionary ▲

sell short
to underestimate oneself or someone else
My friend is selling himself short when he thinks that he will not be good at any other job.

[TahlilGaran] English Idioms Dictionary ▲

sell short
v. To think (a person or thing) less good or valuable than is true; underestimate.
Don't sell the team short; the players are better than you think.
Some teachers sold John short.

[TahlilGaran] English Idioms Dictionary ▲