noun which may take the genitive case particle 'no', noun
ungrateful; unappreciative
Describes a person or attitude that does not show gratitude for kindness or help received. Often used in phrases like 感謝知らずな人 or 感謝知らずの態度.
彼はいつも感謝知らずで、誰かが手伝ってもお礼を言わない。
He is always ungrateful and never says thank you even when someone helps him.
そんな感謝知らずな態度は周りの人を傷つけるよ。
That kind of ungrateful attitude hurts the people around you.
感謝 is the noun for gratitude; 感謝知らず is the negative compound meaning 'without gratitude'.
Compound of 感謝 (gratitude) + 知らず (not knowing), literally 'not knowing gratitude'.