a baby, an infant (human or animal)

赤ちゃん: baby

(onomatopoeia) rattlingly / (onomatopoeia, figuratively) entirely, destructively / (onomatopoeia) with sound of sliding door

rattle (baby's toy)

(onomatopoeia) empty, not crowded, vacant / (onomatopoeia) raspy (voice)

(onomatopoeia) rattle, gargle

to laugh / to smile

to shake; (of a hand or flag) to wave; (of a tail) to wag; (of a baseball bat) to swing; to move something back and forth in a circular motion

swing, wield, flourish, wave, shake

assuming the air of, acting like it (when one is not)