効果【こうか】
effect, effectiveness, efficacy, result, effects (e.g. sound effects, visual effects, special effects)
効く【きく】
to be effective, to take effect, to be good (for), to work, to function well, to be possible (to do, use, etc.), to be able to, to taste (alcohol), to try
無効【むこう】
invalid, void, ineffective, unavailable
有効【ゆうこう】
valid, effective, yuko (judo)
効果的【こうかてき】
effective, successful
効率【こうりつ】
efficiency
時効【じこう】
statute of limitations, lapse of rights after a period of time, prescription (including acquisitive and extinctive prescription), becoming invalid or void after a set time, ageing, aging
効力【こうりょく】
effect, efficacy, validity, potency
逆効果【ぎゃくこうか】
opposite effect, adverse effect, backfiring
効き目【ききめ】
effect, virtue, efficacy, impression, one's dominant eye
実効【じっこう】
practical effect, efficacy, efficiency
発効【はっこう】
coming into effect
効率的【こうりつてき】
efficient
効用【こうよう】
use, utility, effect, benefit
即効【そっこう】
immediate effect, instant effect
特効薬【とっこうやく】
specific medicine, wonder drug, silver bullet
効能【こうのう】
effect, effectiveness, efficacy, virtue, benefit
薬効【やっこう】
medical efficacy, effect of a medicine
失効【しっこう】
lapse, abatement, invalidation, expiration, expiry, becoming void
音響効果【おんきょうこうか】
sound effects, acoustics