practice (learning or improvement of a skill)

practice

excessively, recklessly, randomly

random

randomly, rashly, thoughtlessly, absurdly, indiscriminately

nothing, nothingness / (Buddhism) mu; the null set: neither yes nor no (in response to a koan or other question that mistakenly assumes an affirmative or negative answer).

(archery, weaponry) an arrow / a wedge used to break hard objects such as wood or stone / a 家紋 (kamon, “family crest”) with various designs of arrows

effective

efficacy, benefit, effect

non-, un- / non-, un-