UNGRA'TEFUL, adjective 1. Not grateful; not feeling thankful for favors. 2. Not making returns, or making ill returns for kindness. 3. Making no returns for culture; as an ungrateful soil 4. Unpleasing; unacceptable. Harsh sounds are ungrateful to the ear.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI