IPA: //ˈnʌn.sʌtʃ//
KK: /nʌnˈsʌtʃ/
A person or thing that is regarded as the best or perfect example of its kind.
In the world of classical music, she is a nonsuch, admired by all for her talent.
Nonsuch → It is formed from "non-" (meaning not) and "such" (meaning of that kind). The word "nonsuch" refers to something that is unparalleled or without equal, indicating that there is no other of its kind.
Think of 'not' ('non-') and 'of that kind' ('such') to remember that 'nonsuch' means something that has no equal or is unmatched.