clandestine

(klan-DES-tun)

adj. hidden, secret, concealed.

covert

(KOH-vert)

adj. secret, hidden

furtive

(FUR-tiv)

adj. sneaky

inconspicuous

(in-kun-SPIH-kyoo-wus)

adj. hardly noticeable

sly

(SLIE)

adj. underhanded, furtive

stealthy

(STEL-thee)

adj. secretive, sly

surrepetitious

(sur-up-TIH-shus)

adj. done or made in a secret, stealthy way

unobstrusive

(un-ub-TROO-siv)

adj. inconspicuous; not easily noticed