fly

1 fly /ˈflaɪ/ verb
flies; flew /ˈfluː/ ; flown /ˈfloʊn/ ; flying
1 fly
/ˈflaɪ/
verb
flies; flew /ˈfluː/ ; flown /ˈfloʊn/ ; flying
Britannica Dictionary definition of FLY
1 
[no object] : to move through the air with wings
2 
[no object] : to move through the air especially at a high speed
— often used figuratively
3 
a  : to control an airplane, helicopter, etc., as it moves through the air : to be the pilot of an aircraft
[+ object]
[no object]
b  [+ object] : to journey over (something, such as an ocean) by flying an airplane
4 
a  [no object] : to travel in an aircraft or spacecraft
b  [+ object] : to travel by flying on (a particular airline)
c  [+ object] : to carry (someone or something) to a place in an aircraft
5 
a  : to show (something, such as a flag) by putting it in a high place
[+ object]
[no object]
— see also fly the flag at 1flag
b  [+ object] : to cause (something, such as a kite) to fly in the air — see also go fly a kite at kite
6 
[no object] : to move or go quickly
7 
[no object] : to move freely
8 
[no object] : to pass very quickly
9 
[no object] chiefly US, informal : to be approved or accepted — usually used in negative statements

as the crow flies

— see 1crow

fly at

[phrasal verb]
fly at (someone)
: to attack (someone) with sudden violence

fly high

informal
1 
: to be very happy and excited
2 
: to be very successful

fly in the face of

also US fly in the teeth of
: to fail completely to agree with (something) : to oppose or contradict (something) directly

fly into

[phrasal verb]
fly into (something)
: to be overcome by (sudden extreme emotion)

fly off the handle

informal
: to lose control of your emotions : to become very angry

fly the coop

informal
: to leave suddenly or secretly : to escape or go away

let fly

informal or let fly with
: to throw (something) in a forceful way — often used figuratively
2 fly /ˈflaɪ/ verb
flies; flied; flying
2 fly
/ˈflaɪ/
verb
flies; flied; flying
Britannica Dictionary definition of FLY
[no object] baseball
: to hit a fly ball
3 fly /ˈflaɪ/ noun
plural flies
3 fly
/ˈflaɪ/
noun
plural flies
Britannica Dictionary definition of FLY
[count]
1 
: a small insect that has two wings
2 
: a hook that is designed to look like an insect and that is used for catching fish — see also fly-fishing

drop like flies

informal also die like flies
◊ If people or animals are dropping/dying like flies, they are dropping or dying very quickly in large numbers.
◊ These phrases are often used figuratively.

fly in the ointment

: someone or something that causes problems

fly on the wall

: someone who secretly watches or listens to other people

no flies on

chiefly British, informal
◊ If there are no flies on you, you are a smart person who is quick to understand things and not easily fooled.

wouldn't hurt a fly

◊ Someone who wouldn't hurt a fly is too gentle to want to hurt anyone.
4 fly /ˈflaɪ/ noun
plural flies
4 fly
/ˈflaɪ/
noun
plural flies
Britannica Dictionary definition of FLY
[count]
1 
: an opening in a piece of clothing (such as a pair of trousers, shorts, or a skirt) that is hidden by a fold of cloth and that is closed by a zipper or a row of buttons — sometimes plural in British English — see color picture on this page

on the fly

1 
: quickly and often without preparation
2 
: through the air : without hitting the ground
3 
: while something else is also being done on a computer