Adjectives ending in -ly
Most adverbs end in -ly. There are also some adjectives ending in -ly. Examples are: costly, cowardly, deadly, friendly, likely, lively, lonely, lovely, silly, ugly etc.
- She is a lovely girl. (Here lovely is an adjective. It modifies the noun girl.)
- I love his friendly nature. (Here the adjective friendly modifies the noun nature.)
There are no adverbs friendly / friendlily, lovely / lovelily etc.
Some words can be used both as adjectives and as adverbs. Examples are: daily, weekly, monthly, yearly, early, leisurely etc.
- We should catch an early train. (Here early is an adjective. It modifies the noun train.)
- I got up early. (Here early is an adverb. It modifies the verb got up.)
Adjectives and adverbs with the same form
Some adjectives and adverbs have the same form. Examples are: fast and hard.
- A fast car goes fast.
- If you do hard work, you work hard.
In some cases, the adverb may have two forms: one like the adjective and the other ending in -ly. There is usually a difference of meaning or use.
Examples are: dead and deadly, fine and finely, free and freely, hard and hardly etc.
The adverb dead is used in some expressions to mean ‘exactly’ or ‘very’.
- He was dead drunk.
Note that deadly is an adjective meaning ‘fatal’. The adverb for this meaning is fatally.
- She was fatally injured in the accident. (NOT She was deadly injured in the accident.)