IPA: /ˌsɜːrəpˈtɪʃəsli/
KK: /sɜːrɛpˈtɪʃəsli/
In a way that is done secretly or quietly, often to avoid being noticed or to keep something hidden.
She surreptitiously glanced at her phone during the meeting.
Surreptitiously → It is formed from "surreptitius" (from Latin, meaning stolen or secretly obtained) and the adverbial suffix "-ly" (meaning in a manner of). The word describes an action done in a secretive or stealthy manner, as if it were stolen.
Think of something being done 'secretly' or 'stolen' — 'surreptitiously' means acting in a way that is hidden or not openly acknowledged.