adverb
easily; without difficulty; with no trouble
Describes doing something effortlessly, often with a nuance of not even needing to use one's hands. Used adverbially.
彼はその問題を手も無く解いた。
He solved the problem easily.
相手チームを手も無く倒した。
They defeated the opposing team with no trouble.
簡単に is a more common and neutral way to say 'easily'. 手も無く emphasizes effortlessness, often with a nuance of not even needing to use one's hands.
楽々 also means 'easily' but focuses on comfort and lack of strain, while 手も無く highlights the absence of difficulty or resistance.
From 手 (hand) + も (even) + 無く (without), literally 'without even using hands', implying something is so easy that no manual effort is required.