奇 strange

It's possible for a KEY to be over 10 feet big, but it would be a little strange.

weird ★★☆☆☆
奇 (strange) + 妙 (odd) = 奇妙 (weird)

weird - but more broad than the related term 妙. 奇妙 means unusual and absurd - a street-person wearing a duck as a hat is 奇妙.

curiosity ★☆☆☆☆
好 (like) + 奇 (strange) + 心 (heart) = 好奇心 (curiosity)

curiosity

BOOBOO: if you want to say you're curious about a specific thing, you'd use 興味　（きょうみ） instead.

好奇心 usually means "curiosity-in-general": 　you have an inquiring personality, or a gaze of curiosity on your face. You'd never say, "Oh, you play in a band? 好奇心ある！”