猿に烏帽子
(Saru ni eboshi; “A courtier’s cap on a monkey”)

Definition:

When the appearance of something is all dressed up, but doesn’t match its real content. Alternately, unfitting behavior. Like putting a fancy hat of the kind that used to be worn by aristocratic men in the imperial court… on a monkey. Like lipstick on a pig, or an expensive suit on an evil clown, but perhaps cuter.

Breakdown:

This simple phrase begins with the noun 猿 (saru), “monkey,” and ends with the noun 烏帽子 (eboshi), which is the name of a style of hat worn by Japanese court officials back in the day, based on a design imported from the mainland. They’re joined by the particle に (ni), which applies the latter noun to the former. The causative form of a verb such as 被る (kaburu), “to wear (on one’s head),” is implied but elided.

Notes:

There are several variants of this phrase, mostly replacing 烏帽子 with 冠 (kanmuri), “crown,” or the more generic 衣 (koromo), “clothing.”

This is a common style of eboshi, by the way:

Source: Wikimedia Commons

Example sentence:

「いやあ、いつも砕けた雰囲気が漂うあの人があんな固い言い方で話すなんて、まるで猿に烏帽子だ。違和感しかないね。」

(“Iyaa, itsumo kudaketa fun’iki ga tadayou ano hito ga anna katai iikata de hanasu nante, maru de saru ni eboshi da. Iwakan shika nai ne.”)

[“Naaah, they always have such a laid-back attitude that when they talk in a formal way it feels really inappropriate. It just makes me uneasy.”]

Ironically, Lady Eboshi wore a kasa-style hat.