なんnante
1.

An expression used to convey strong feelings of surprise or admiration, often highlighting an impressive or endearing quality of something.

2.

A colloquial form of "what" or "how" that expresses disbelief or amazement about a situation or characteristic, often used in informal contexts.

3.

A casual phrase for referring to something in a manner that indicates a lack of formality or precision, often accompanied by a sense of curiosity or inquiry regarding its nature or qualities.

Example:

彼はなんて大食らいなんだろう。