口輪 is read as くちわ (kuchiwa) and means muzzle.
くちわ
kuchiwa
こうりんきん
orbicularis oris muscle
くちべに
lipstick
こうじゅつ
dictation
くちうら
divining good or bad luck from listening to someone
こうかく
corners of the mouth
くちざみせん
humming a samisen tune
くちなし
non-functional mouth
こうじゅつしょ
affidavit
こうじゅつけん
public recitation right (e.g. reciting a poem in a bookstore)
くちずもう
kissing
こうへん
around one's lips
こうへんに
around the mouth