(idiomatic) to be sharp; to be keen; to be on the ball; to have a mind like a steel trap; to be clever

(idiomatic) to get mad; to be highly offended; to get pissed off; to get angry; to lose one's cool

(idiomatic) insane, crazy, nuts, out of one's mind

Alternative form of 頭がおかしい

(slang) a forgetful person

long sword with birds' heads carved on the pommel

the above / the top (position or direction) / the surface of / superior in skill, age, level, etc.

in addition; furthermore / on top of (which)

incline, tilt, slant

a quadriceps femoris muscle