to betray

behind; at the back; in the rear; behind sb's back

background; backdrop; context; (fig.) powerful backer

carrying on one's back

turning one's back to (sth or sb); keeping sth secret from (sb); keeping (one's hands) behind one's back

to go against; to be contrary to; to violate

the back (human anatomy); the back part of sth

hunchbacked; stooping; hunchback

back of the hand

back of the knife