Oxford Dictionary English

    fly

    noun
    noun
    BrE BrE//flaɪ//
    ; NAmE NAmE//flaɪ//
    (pl. flies) Invertebrates
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    insect
  1. 1 [countable] a small flying insect with two wings. There are many different types of fly. A fly was buzzing against the window. Flies rose in thick black swarms. Oxford Collocations Dictionary verb + flyshoo, shoo away, swat, … fly + verbbuzz, crawl, land (on something), … fly + nounlarva, spray See full entry See related entries: Invertebrates
    2.  in fishing
  2. 2[countable] a fly or something made to look like a fly, that is put on a hook and used as bait to catch fish fly fishing Wordfinderfishingbait, bite, dragnet, fishing, fly, hook, line, net, rod, trawl
    3.  on trousers/pants
  3. 3[singular] (British English also flies) an opening down the front of a pair of trousers/pants that fastens with a zip or buttons and is usually covered over by a strip of material Your fly is undone! Your flies are undone! Oxford Collocations Dictionary adjectivebutton verb + fly/​fliesbutton, button up, do up, … fly + nounbutton See full entry
    4.  on tent
  4. 4[countable] a piece of material that covers the entrance to a tent
    5. see also flies     Word Originnoun senses 3 to 4 Old English flēogan, of Germanic origin; related to Dutch vliegen and German fliegen, also to fly, the insect. noun senses 1 to 2 Old English flȳge, flēoge, denoting any winged insect, of West Germanic origin; related to Dutch vlieg and German Fliege, also to fly (verb). Extra examplesA fly settled on the butter. Do you know your flies are undone? I swatted the fly with a newspaper.Idioms
    die/fall/drop like flies
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    (informal) to die or fall down in very large numbers People were dropping like flies in the intense heat.
    a/the fly in the ointment
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    a person or thing that spoils a situation or an occasion that is fine in all other ways
    a fly on the wall
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    a person who watches others without being noticed I'd love to be a fly on the wall when he tells her the news. fly-on-the-wall documentaries (= in which people are filmed going about their normal lives as if the camera were not there)
    (there are) no flies on somebody
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    (informal) the person mentioned is clever and not easily tricked
    not harm/hurt a fly
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    to be kind and gentle and unwilling to cause unhappiness
    on the fly
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    (informal) if you do something on the fly, you do it quickly while something else is happening, and without thinking about it very much
See fly in the Oxford Learner's Dictionary of Academic EnglishSee fly in the Oxford Advanced American Dictionary
Check pronunciation: fly
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