IPA: //stæɡˈneɪt//
KK: /stægˈneɪt/
To stop developing or progressing; to remain unchanged or inactive.
If you don't challenge yourself, your skills will stagnate over time.
Past: stagnated
Past Participle: stagnated
Stagnate → It is formed from "stagnare" (meaning to stand still or to be stagnant) which comes from the Latin root "stagnus" (meaning standing water). The word describes the process of becoming inactive or not flowing, much like water that is not moving.
Think of water that is 'standing still' — that's what stagnate means, to become inactive or not flow.