Adjectives or adverbs? confusing cases

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.)

Fine and finely

The adverb fine means ‘well’. It is used in some informal expressions.

• She is doing fine.

The adverb finely is used to talk about small careful adjustments.

• finely ground particles
• a finely tuned machine

Free and freely

The adverb free means ‘without payment’. The adverb freely means ‘without restriction’.

• Buy two shirts and get one free.
• Speak freely. (= Speak without fear or inhibition.)

Hard and hardly

The adverb hard has a similar meaning to the adjective hard.

• He works hard.
• Hit it hard.

Hardly has a negative meaning. It means ‘almost not’.

• We have got hardly any rice left.

High and highly

High is used to talk about height. Highly often means ‘very much’.

• He threw it as high as he could.
• It is highly amusing.

Late and lately

The adverb late has a similar meaning to the adjective late. Lately means ‘recently’.

• He arrived late.
• Have you read anything interesting lately?

Most and mostly

Most is the superlative form of much.

• This is the most interesting film I have ever seen.

Most can mean ‘very’ in a very formal style.

• It is a most interesting novel. (= It is a very interesting novel.)

Mostly means ‘mainly’.

• My friends are mostly vegetarians.

Real and really

In informal American English, real is often used instead of really.

• She sings real well. (= She sings really well.)