礼 polite

The polite necrophiliac kept his lovers on meat-hooks, so RAY wouldn't step on them when he came over. Thoughtful!

rude ★★★★☆
失 (miss out on) + 礼 (polite) = 失礼 (rude)

rude, without manners.

in thanks for ★★★☆☆

in thanks for. As in, "In thanks for the sweater, I bought him a moray eel."

Formal manners ★★☆☆☆
礼 (polite) + 儀 (politeness) = 礼儀 (Formal manners)

Manners used in formal situations: correct bowing proceedures, sonkeigo, respecting heirarchy.

key money ★★☆☆☆
礼 (polite) + 金 (gold) = 礼金 (key money)

literally 'politeness money.' - sometimes the phrase "key money" is also used - as if that explains anything. This is the legalized bribe you pay for the privilege of paying rent on a new apartment.