The Adverb of High: Highly
The adverb of high is highly.
How highly is formed
Add -ly with no change: high + ly = highly. But this is one of the cases where the plain adjective is also an adverb, and the two are not interchangeable.
A small but important group where both forms exist with different meanings: high / highly, deep / deeply, hard / hardly, late / lately, near / nearly. In each pair the plain form is literal and the -ly form is figurative.
Highly in a sentence
| The kite flew high above the trees. | Physical height. Highly would be wrong here. |
| She is highly regarded in the field. | Figurative: to a great degree. |
| It is highly unlikely. | Intensifying an adjective. |
Where it is actually used
Knowing the form is one thing; knowing the company a word keeps is what makes it sound natural. These are the patterns highly appears in most often.
| highly regarded / respected / skilled | Judgement of a person. The dominant use. |
| highly unlikely / unusual / effective | Intensifying an adjective. |
| fly / aim / climb high | The plain form, for literal height and for ambition. |
Highly or something else?
Several adverbs sit close to highly, and the difference is usually meaning rather than formality.
| greatly | Similar in the figurative sense, but does not attach to adjectives. Greatly unlikely is not English. |
| extremely | Stronger, and more freely attached to almost any adjective. |
| very | The plainest option, and the one to use when highly would sound overblown. |
The mistake to watch for
| Incorrect | Correct |
| The bird flew highly. | The bird flew high. |
For actual height, English uses the plain form. Highly has moved entirely into the figurative sense and cannot describe a position in the air.
The literal and figurative split. Compare hard and hardly: she works hard and she hardly works mean opposite things. High and highly have not diverged that far, but the same principle is at work – when a language keeps two adverbs from one adjective, it gives them different jobs.
Related forms
Pronunciation: HIGH-lee, two syllables.
| Adjective | high |
| Adverb (literal) | high – aim high, fly high |
| Adverb (figurative) | highly – highly skilled |
| Noun | height |
Practice
Fill the gap, then check yourself.
- The plane climbed ___ above the clouds.
- He is ___ regarded by his colleagues.
- It is ___ improbable that they will agree.
Answers: 1. high 2. highly 3. highly
Frequently asked
Can I say highly recommended?
Yes, and it is the standard phrase. Highly works freely before past participles: highly recommended, highly trained, highly prized.
