1 screw /ˈskruː/ noun
plural screws
1 screw
plural screws
Learner's definition of SCREW
: a narrow, pointed metal cylinder that has a wide flat or rounded top and a ridge (called a thread) that goes around it in a spiral
◊ A screw is used to hold things together or to attach things. It is inserted into wood, metal, etc., by being turned.
see picture at carpentry; compare 1nail 1
: an object that has a thread like a screw which is used to attach or connect it to something usually used before another noun
informal + offensive
: an act of sexual intercourse
: a sexual partner
slang : a prison guard

have a screw loose

informal or have a loose screw
: to be crazy

put the screws on/to (someone or something)

: to use force or the threat of force to make (someone or something) do what you want

tighten the screws

: to put more pressure on someone or something to do something
2 screw /ˈskruː/ verb
screws; screwed; screwing
2 screw
screws; screwed; screwing
Learner's definition of SCREW
always followed by an adverb or preposition, [+ object] : to attach (something) with a screw
always followed by an adverb or preposition
[+ object] : to turn (something) so that it attaches or connects to something
[no object] : to fit onto or into something by being turned
informal + offensive
[no object] : to have sex
[+ object] : to have sex with (someone)
[+ object] informal
: to take something from (someone) by lying or breaking a rule
often + out of
: to prevent (someone) from having or getting something that is deserved or expected often + out of or (US) over
[+ object] informal + impolite used to express anger, disgust, etc.
[+ object] : to press or squeeze (something) so that it is no longer flat or smooth often + up

have/get your head screwed on right/straight

see 1head

screw around

[phrasal verb] chiefly US, informal
: to do things that are not useful or serious : to waste time
: to have sex with someone who is not your husband, wife, or regular partner
often + with
: to use or do something in a way that is not very serious
often + with
screw around with (something) : to handle or play with (something) in a careless or foolish way

screw up

[phrasal verb] informal
: to make a mistake : to do something incorrectly
screw (something) up or screw up (something) : to make a mistake in (something)
screw (something) up or screw up (something) : to damage or ruin (something) : to damage or change (something) so that it does not work properly
screw (someone) up or screw up (someone) : to make (someone) very upset and unhappy for a long time
screw (something) up or screw up (something) : to tighten the muscles of (your face or eyes)
screw up the/your courage : to make yourself brave enough to do something difficult
see also 2screw 6