as one wishes; as one pleases; to one's heart's content
Expresses doing something freely, without restraint, exactly as one desires. Often used adverbially with に or as a noun with だ/の.
I want to spend my day off as I please.
彼は思うままの人生を送っている。
He is living life on his own terms.
Rarely used kanji form with 儘.
Compound of 思う (omou, 'to think, feel') and まま (mama, 'as it is, condition'). The exact historical derivation is straightforward; まま indicates the state of one's thoughts or desires.