漫无目的

• 氵(water)RADICAL
• 曼(extend; spread)PHONO-SEMANTIC

Water spreads everywhere, stretching endlessly like vast rivers.

• 一(one; initial)ASSOCIATIVE
• 尢(disabled person; insufficient)ASSOCIATIVE

From the beginning there was a shortage, so 無 means 'nothing at all'.

• 白(white; bright)RADICAL
• 勺(spoon)PHONETIC

A spoon catching sunlight shines brightly and clearly — the character means "of" or shows clarity and definiteness.