# fly

/ˈfɫaɪ/ (US) · /flˈaɪ/ (UK)

Source: https://englishreference.com/word/fly
Updated: 2026-06-19

## Senses

### 1. to move through the air

verb · CEFR A1

to move through the air using wings or an aircraft.

For teachers: to move through the air or space under one's own power or by means of an aircraft. Intransitive in this sense.

- The birds fly south every year when the weather starts to get cold.
- The pilot managed to fly the damaged aircraft through the storm, landing safely despite the failing engine.

### 2. to move very fast

verb · CEFR B1 · Informal

to move or go somewhere very quickly.

For teachers: to move, pass, or progress with great speed or haste.

- I have to fly or I will be late for my doctor's appointment.
- Time seemed to fly during the summer holidays, leaving the students unprepared for the sudden return to their studies.

Teaching tip: Often used with 'time' to express how quickly a period has passed.

### 3. to be accepted

verb · CEFR B2 · Informal

to be successful or accepted by other people.

For teachers: to be valid, acceptable, or successful in a particular context.

- That excuse about your dog eating your homework just won't fly with the teacher.
- The board of directors made it clear that the proposed budget cuts simply would not fly in the current economic climate.

Usage: Usually used in the negative to mean a plan or excuse will not be believed.

### 4. to display a flag

verb · CEFR B1

to show a flag by hanging it from a pole.

For teachers: to display a flag or banner from a pole or mast. Transitive use.

- The ship was flying a red flag to warn other boats of the danger.
- Every government building in the capital was required to fly the national colours during the independence celebrations.

### 5. the insect

noun · CEFR A2

a small insect with two wings that often makes a buzzing sound.

For teachers: any two-winged insect of the order Diptera, specifically the common housefly.

- A fly was buzzing around the kitchen while I was trying to cook dinner.
- The biologist observed the fly under the microscope to study the intricate structure of its compound eyes.

Usage: The plural is 'flies'.

### 6. trousers opening

noun · CEFR B1

the opening at the front of a pair of trousers that uses a zipper or buttons.

For teachers: an opening at the crotch of a pair of trousers, typically closed by a zipper or buttons and covered by a fabric flap.

- He realized his fly was open just as he walked onto the stage.
- The tailor carefully stitched the fly of the bespoke trousers to ensure the buttons remained hidden behind the silk placket.

Usage: Often used in the plural 'flies' in British English, but singular 'fly' in American English.

### 7. fishing lure

noun · CEFR C1 · Technical

a fake insect used as bait to catch fish.

For teachers: an artificial fishing lure made of silk, feathers, or similar material to resemble an insect.

- He spent the afternoon choosing the right fly to catch trout in the river.
- Experienced anglers often tie their own flies, meticulously matching the local insect population to increase their chances of a strike.

### 8. stylish

adjective · CEFR C1 · Slang · Informal

looking very cool, stylish, or attractive.

For teachers: stylish, fashionable, or physically attractive. Primarily used in urban contexts.

- Those new sneakers you bought are looking really fly.
- He showed up to the party looking fly in a vintage leather jacket and designer sunglasses.

Teaching tip: This term was very popular in 1990s hip-hop culture; it is still used but can feel slightly dated to some speakers.

## Examples

- A fly is buzzing around the room.
- He waved his hand to shoo a fly away from his lunch.
- The still life painting was so realistic you could almost see the shimmer on the wings of the fly resting on the pear.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.