Adverb meaning something is done with little effort or trouble.
He solved the problem easily.
This job will probably be finished without difficulty.
Kanji form; rarely used.
Kanji form with 無; rarely used.
From 訳 (わけ, 'reason') + なく (adverbial form of ない, 'not'), literally 'without reason (for difficulty)'. The exact historical derivation is uncertain.