IPA: /ˈstɛlθɪli/
KK: /ˈstɛlθɪli/
In a way that is quiet and secret, so that others do not notice.
The cat moved stealthily through the tall grass, trying not to be seen.
Stealthily → It is formed from "stealth" (from Old English *stielþ*, meaning secret or hidden) and the suffix "-ily" (meaning in a manner). The word "stealthily" means in a secret or hidden manner.
Think of doing something in a 'hidden' way ('stealth') — the '-ily' just means how you do it. This helps you remember that 'stealthily' means to act in a secretive manner.