furtively

the adverb 'furtively' is built upon the adjective 'furtive', which has a direct lineage to latin. the latin root furtum meant 'theft' or 'a stolen thing', and the adjective furtivus described something obtained by theft or done by stealth. this concrete association with thievery and secrecy evolved into the more general modern sense of acting in a sly, stealthy manner to avoid detection. the addition of the old english adverbial suffix '-ly' transforms the descriptive adjective into a word that modifies an action, encapsulating the manner of doing something with concealed intention.

Structure: furtive + ly furtive (from latin furtivus, meaning 'stolen, hidden', from furtum 'theft') + ly (from old english -līce, an adverbial suffix).