Autoantonym vs Wordbuilding - What's the difference?

As nouns the difference between autoantonym and wordbuilding

is that autoantonym is a word that has two opposing meanings while wordbuilding is the construction of words from simpler units.

(wikipedia autoantonym)

(en noun)

(rare) A word that has two opposing meanings.

Left: a word that can mean "to have departed from" or "to have remained".

Dust: means "to remove dust from" or "to spray or cover something with fine powder".

Awful: means "terrible" or "magnificent".

* contranym, contronym

(-)

The construction of words from simpler units.

We gave the children a wordbuilding exercise.

* (l)