n.
        - a short, slender, sharp-pointed metal pin with a raised helical thread running around it and a slotted head, used to join things together by being rotated in under pressure. 
▸a cylinder with a helical ridge or thread running round the outside that can be turned to seal an opening, apply pressure, adjust position, etc.
 ▸
(the screws)
 historical an instrument of torture acting in this way.
 - an act of turning a screw. 
▸Brit. a small twisted-up piece of paper containing a substance such as salt or tobacco.
 - 
(also screw propeller)
 a ship's or aircraft's propeller.
 - informal, derogatory a prison warder.
 - vulgar slang an act of sexual intercourse.
 - Brit. informal, dated an amount of salary or wages.
 - archaic, informal a mean or miserly person.
 - Brit. informal a worn-out horse.
 
v.
   - fasten or tighten with a screw or screws. 
▸rotate (something) so as to attach or remove it by means of a spiral thread.
 ▸impart spin or curl to (a ball or shot).
 ▸
(screw something around/round)
 turn one's head or body round sharply.
 - informal cheat or swindle. 
▸ruin or render ineffective.
 - vulgar slang have sex with.
 
 
  Phrase
  
    - have one's head screwed on 
(the right way)
 informal have common sense.  - have a screw loose
 informal be slightly eccentric or mentally disturbed.  - put 
(or turn or tighten)
 the screw 
(or screws)
 on
 informal exert strong psychological pressure on. 
   
  Phrase verbal
  
    - screw around
  - vulgar slang have many different sexual partners.
 - informal fool about.
 
  - screw someone over
 informal, chiefly US treat someone unfairly; cheat or swindle someone.  - screw up
 informal completely mismanage or mishandle a situation.  - screw someone up
 informal cause someone to be emotionally or mentally disturbed.  - screw something up
   - crush a piece of paper or fabric into a tight mass. 
▸tense the muscles of one's face or around one's eyes.
 - informal cause something to go wrong.
 - summon up one's courage.
 
 
   
  Derivative
  
    - screwable adj.
  - screwer n.
 
   
  Etymology
  ME (as n.): from OFr. escroue ‘female screw, nut’, from L. scrofa, lit. ‘sow’, later ‘screw’.