expression, godan verb (-ku)
bare one's fangs; snarl (at)
Literally for animals showing teeth aggressively; figuratively for a person showing open hostility or anger.
犬が突然牙を剥いて唸り始めた。
The dog suddenly bared its fangs and started growling.
彼は普段は穏やかだが、時々牙を剥くことがある。
He is usually gentle, but sometimes he shows his fangs.