furtive
Concise Oxford English Dictionary © 2008 Oxford University Press:
furtive /ˈfəːtɪv/
▶adjective characterized by guilty or evasive secrecy.
– derivatives
furtively adverb,
furtiveness noun.
furtively adverb,
furtiveness noun.
– origin C17: from Fr. furtif, -ive or L. furtivus, from furtum ‘theft’.
'furtive' also found in these Oxford entries:

