bad, vice, rascal, false, evil, wrong
悪 centers on moral or qualitative wrongness: something bad, evil, or false. It extends naturally to a person who embodies that wrongness, like a rascal or villain.
悪 is the modern simplified form of 惡. The older form combines 亞 (likely contributing sound) with 心 (heart/mind), suggesting a twisted or bad heart. The modern 亜 is a simplification of 亞.
The top 亜 looks like a crooked, blocked shape, and the bottom 心 is the heart. Picture a twisted heart producing bad, evil thoughts.
For アク, imagine an evil act so bad it makes you say 'ack!' in disgust: ack -> アク, and the twisted heart 悪 is behind it.
bad; poor; undesirable
worst
devil; demon; fiend
deterioration; getting worse; worsening; aggravation; degeneration; corruption
malicious; vicious; malignant; underhanded
(verbal) abuse; name-calling; abusive language; insulting remarks
(verbal) abuse; speaking ill of people; bad-mouthing; name-calling; slander; abusive language; insulting remarks
nightmare; bad dream
ill will; spite; evil intention; malice
mischief; prank; trick; practical joke
disgust; hate; repugnance; loathing
bad influence; negative influence
villain; baddie; the villain's part
atrocious; heinous; fiendish; brutal; vicious
bad person; villain; scoundrel; wrongdoer; wicked person
hatred; abhorrence; loathing; detestation
abuse; misuse; perversion
vice; immorality; corruption
bad guy; villain; evildoer; scoundrel
evil deed; wrongdoing; crime; vice
evil; wickedness
malicious; ill-tempered; unkind; mean; nasty
right and wrong; good and evil
malignant (cancer); virulent; pernicious (anemia, anaemia)
bad weather
ill will; malice; evil intent
vicious circle; vicious cycle
bad smell; foul smell; offensive odor; stench; stink
poor (quality, conditions, etc.); bad; inferior; poor-quality
wicked woman
coarse; crude; inferior
ugly; unsightly; hideous; mean; repulsive; disgraceful
dangerous; perilous; threatening; stormy; volatile; tense; critical; serious
morning sickness; nausea and vomiting of pregnancy
chill; shakes; ague
don't get me wrong, but ...; I'm sorry
right or wrong; good or bad; quality; suitability
rewarding good and punishing evil; poetic justice
(feeling of) hatred; (strong) dislike; disgust; aversion; revulsion; loathing; abhorrence
badness; mean mischief
cunning; crafty; wily; sly
unpleasant; revolting; repulsive; gross; disgusting; disturbing; creepy