be all that

be all that

To be remarkably adept, intelligent, good-looking, or successful. Primarily heard in US, South Africa. I don't need to see his test results, I already know he's all that!
See also: all, that

all that

1. Too, very, usually employed in a negative context meaning not too, not very. For example, The new house is not all that different from your old one. [Mid-1900s] Also see none too.
2. That and everything else of the kind. For example, She enjoys wearing nice clothes and perfume and all that. [c. 1700] Also see and all.
3. See for all that.
See also: all, that

be all that

AMERICAN, INFORMAL
If someone or something is all that, they are very impressive and of a high quality. My boyfriend thinks he's all that. I read the book because my friend thinks it's all that.
See also: all, that

be all that

be very attractive or good. US informal
2002 Guardian I can't believe how she throws herself at guys, she thinks she's all that.
See also: all, that

be all ˈthat

(American English, informal) be very attractive or impressive: He thinks he’s all that.
See also: all, that

all that

Informal
To the degree expected.
See also: all, that
References in classic literature ?
Beth said nothing, but wiped away her tears with the blue army sock and began to knit with all her might, losing no time in doing the duty that lay nearest her, while she resolved in her quiet little soul to be all that Father hoped to find her when the year brought round the happy coming home.