un-, mistake, negative, injustice, non-
非 centers on negation and wrongness: the idea of something being not right, a mistake, or an injustice. The prefix senses like "un-" and "non-" are direct applications of this negative core.
非 is a pictograph of two opposing wings or a divided shape, representing opposition or negation. The modern form retains the symmetrical, split appearance that suggests something contrary or wrong.
The two sides of 非 look like mirror images that are slightly off, like a mistake or something that is not right. Picture two wings flapping in opposite directions, symbolizing negation and injustice.
For ヒ, imagine a person saying "he" is wrong: "he" -> ヒ, and the mistake is clear in the opposing wings of 非.
emergency
fault; error; mistake
certainly; without fail
criticism; blame; censure; attack; reproach
private; non-public; secret; closed-door; closed
informal; unofficial
lack of common sense; thoughtlessness; senselessness; irrationality; absurdity
by all means; at all costs; absolutely
part-time work
unjust; inhuman
cold-hearted; callous; unfeeling; cruel
time of emergency; (in an) emergency
illegal; unlawful
false; pseudo-; quasi-; would-be; sham; pretended; mock
article not for sale
asymmetry; dissymmetry; unsymmetry
non-nuclear; anti-nuclear
delinquency; misconduct
tax-exempt; tax-free; tax-exempted
powerless; helpless; incompetent