entrance,
opening, door, doorway, aperture, gate, gateway, means of access, entry, way in,
way out, exit
insolence,
impertinence, lip (slang), rudeness, back talk, cheek (UK, informal), backchat
(UK, informal)
estuary,
outlet, bay, inlet
adenoids, denture, gum, lip, palate,
roof, soft palate, taste bud, tongue, tonsils, tooth,
uvula