IPA: /ˈsniːkɪli/
KK: /ˈsniːkɪli/
In a way that is secretive or intended to avoid being noticed.
He sneakily took the last cookie from the jar without anyone seeing.
Sneakily is formed from "sneak" (of uncertain origin, possibly from Middle Dutch "sneken", meaning to creep or move stealthily) and the suffix "-ily" (meaning in a manner). The word describes the manner of doing something in a stealthy or secretive way.
Think of moving in a 'stealthy' way, as 'sneak' suggests creeping quietly, and '-ily' indicates the manner of doing it.