noun which may take the genitive case particle 'no', na-adjective, noun
Describes something that is the other way around, contrary, or inverted in direction, order, or meaning. Used as a noun, な-adjective, or with の.
His opinion is the opposite of mine.
I ended up walking in the opposite direction.
Used in logic or mathematics for the converse of a proposition or hypothesis. Often appears in academic contexts.
The converse of 'if A then B' is 'if B then A'.
Mathematical prefix for inverse functions, e.g., 逆関数 (inverse function). Not used as a standalone word in this sense.
Inverse trigonometric functions are learned in high school.
He holds the opposite opinion from mine.
Contrary to expectations, the exam was easy.
It's easier to understand if you count backwards.
逆 is the broader word for 'reverse/opposite' (direction, order, logic), whereas 逆さ specifically describes something being physically upside down or back-to-front.
逆 is a neutral, everyday word for 'reverse' or 'opposite' (e.g. 逆方向), while 正反対 stresses a total, diametrical contrast, often between two things being compared.
逆 is a general word for 'reverse' or 'opposite', whereas １８０度 specifically emphasizes a complete, dramatic reversal in stance or direction.
backward flow; backflow; reflux; regurgitation
reverse movement; going backwards; retrogression · retrograde motion
adversity; adverse circumstances; unfavorable situation
paradox
frenzy; rage; flying into a rage
counting backwards; calculating backwards; back-calculation · inverse operation
irreversible
headwind; adverse wind
backlight; backlighting
reversible · invertible
rebel; traitor; insurgent
high treason
reverse order; inverted order
atrocity; heinous crime · treason (archaic)
opposite effect; backfiring
rebellion; insurrection; treason
five cardinal sins · crime of killing one's master or close elder relatives
murder of one's lord or father
forward and reverse; normal and reverse
exact opposite; polar opposite
close friendship; cordial relations
conversely; on the contrary; rather
chromosomal inversion