Explanation

Adjectives describe nouns or pronouns.
Superlative adjectives compare differences among 3 or more nouns.

Adjectives with 1-2 syllables use '-est.' Adjectives with 3 or more syllables use 'the most/least.'
Some adjectives have irregular forms.

thing 1 + verb + adjective '-est'
thing 1 + verb + 'the most/least' + adjective

Example

Yesterday was the hottest day of the year.
We had the smallest table.
It is the most beautiful park in the city.
It’s the least crowded restaurant in the city.
That was the worst meal I ever ate.
She is the best teacher.

Common mistakes

Use 'the' with superlative adjectives.