Sense: 1, 3-7, 9
|Origin:||Old English fleoge|
a small flying insect with two wings:
There were flies buzzing all around us.
the part at the front of a pair of trousers which you can open:
trousersespecially American English also flies [plural] British EnglishDCC
He quickly did up his fly.
Your flies are undone.
used to say that someone is very gentle and is not likely to hurt anyone
used to say that a lot of people are dying or becoming ill
the only thing that spoils something and prevents it from being successful:
The only fly in the ointment was Jacky.
to be able to watch what happens without other people knowing that you are there: ➔ fly-on-the-wall
I wish I'd been a fly on the wall during that conversation.
7 British English spoken
used to say that someone is not stupid and cannot be tricked
while a computer program is actually running:
The code is translated on the fly.
while dealing with a situation, rather than before dealing with it:
So far, policy is being made on the fly.
a hook that is made to look like a fly and is used for catching fish
a fly ball