spherical object / ball

a sharp edge (of a ball)

beaten-egg soup

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

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

Alternative form of 頭がおかしい

iridescent; having different colours when the angle of view or illumination changes / ambiguous or vague; using weasel words

(slang) a forgetful person

a head as hard as a stone / stubbornness and inflexibility / an inflexible person

お玉杓子, 御玉杓子: a tadpole