also: てなもん
expression
something like ...; something called ...
Colloquial phrase used to present something as a rough example or to downplay its significance. Often follows a noun or clause and carries a casual, dismissive, or self-deprecating tone. Equivalent to というもの in standard speech.
See also: と言うもの (というもの)
趣味ってなもんは、人それぞれだよ。
Hobbies, or whatever you call them, are different for everyone.
彼の言うことなんて、ただの言い訳ってなもんだ。
What he says is just something like an excuse.