quietly, sneakily, furtively, secretly, covertly, surreptitiously ..
The senator glanced furtively toward his aide as he answered the questions. Furtively means do something with stealth. Synonyms for furtively we would be; secretly, hidden, surreptitiously, slyly, stealthily, underhandedly.
Watch
The word "furtively" is an adverb. It describes how an action is performed, often suggesting secrecy or stealth.
He glanced around furtively before slipping the note into her pocket.
lure
SIDLE
peep
Lookout, watch, sentinel
watch, sleeplessness, wake.
The word "furtively" is an adverb. It describes how an action is done, in a secretive or sneaky manner.
He furtively tip-toed past his parents' room, making sure that he wouldn't wake them up as he snuck out of the house.