Synset

marked by quiet and caution and secrecy; taking pains to avoid being observed
<adj.all>   (a)   freq. cnt.: 2 freq. cnt.: 1 freq. cnt.: 1

furtive

sneak

sneaky

stealthy

surreptitious

sample sentences

"a furtive manner"
"a sneak attack"
"stealthy footsteps"
"a surreptitious glance at his watch"