What you are describing is best classified as a "caconym" or more commonly referred to as a "misnomer".
small, tiny, mini, something in a decreasing size. if that even makes sense. but its true!
Something not big would be small, tiny, diminutive, itsy-bitsy, little.
The opposite of vast would be small, compact, or (to a greater extreme) tiny.
The opposite of 'big' is little.
Particle in the English language refers to the a very tiny piece of something.
'Minute' means something tiny.
small, tiny, mini, something in a decreasing size. if that even makes sense. but its true!
The opposite of huge Is tiny.
small, tiny, mini, something in a decreasing size. if that even makes sense. but its true!
Something not big would be small, tiny, diminutive, itsy-bitsy, little.
Huge
tiny
enormousgiganticspaciouscolossal
The opposite of massively would be minutely, minimally, or negligibly.
The usual opposite is "small" (also little, diminutive, or more extremely, tiny).
The opposite of colossal (huge) could be tiny, small, miniscule, or modest (in size).
tiny