A superlative adjective expresses the extreme or highest degree of a quality. We use a superlative adjective to describe the extreme quality of one thing in a group of things.
We can use superlative adjectives when talking about three or more things (not two things).
Formation of Superlative Adjectives
As with comparative adjectives, there are two ways to form a superlative adjective:
| Short adjectives | |||
| 1-syllable adjectives | old, fast | ||
| 2-syllable adjectives ending in -y | happy, easy | ||
| RULE: add "-est" | old → the oldest | ||
| Variation: if the adjective ends in -e, just add -st | late → the latest | ||
| Variation: if the adjective ends in consonant, vowel, consonant, double the last consonant | big → the biggest | ||
| Variation: if the adjective ends in -y, change the y to i | happy → the happiest | ||
| Long adjectives | |||
| 2-syllable adjectives not ending in -y | modern, pleasant | ||
| all adjectives of 3 or more syllables | expensive, intellectual | ||
| RULE: use "most" | modern → the most modern expensive → the most expensive |
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Exception: The following adjectives have irregular forms:
Use of Superlative Adjectives
We use a superlative adjective to describe one thing in a group of three or more things. Look at these examples:
If we talk about the three planets Earth, Mars and Jupiter, we can use superlative adjectives as shown in the table below:
| Earth | Mars | Jupiter | ||
| Diameter (km) | 12,760 | 6,790 | 142,800 | Jupiter is the biggest. |
| Distance from Sun (million km) | 150 | 228 | 778 | Jupiter is the most distant from the Sun. |
| Length of day (hours) | 24 | 25 | 10 | Jupiter has the shortest day. |
| Moons | 1 | 2 | 16 | Jupiter has the most moons. |
| Surface temp. (degrees Celcius) | 22 | -23 | -150 | Jupiter is the coldest. |