1
general::
Someone or something that is superior to examples of a similar nature, as in This book is a cut above his previous one. This idiom uses cut in the sense of "a higher degree or stage." [Early 1800s]
American Heritage Idioms
2
general::
Phrase(s): a cut above something
a measure or degree better than something else. (See also a cut above average. The cut is a degree or notch.) • Your shirt is beautiful, but mine is a cut above yours.
McGrawhill's American Idioms And Phrasal Verbs