hey
exclamation /heɪ/
  /heɪ/
(informal)Idioms - used to attract somebody’s attention or to express interest, surprise or anger
- Hey, can I just ask you something?
 - Hey, leave my things alone!
 
 - (especially North American English, informal) used to say hello synonym hi
- Hey, Jake! How are you doing?
 
 - used to show that you do not really care about something or that you think it is not important
- That's the third time I've been late this week—but hey!—who's counting?
 
 - (South African English) used at the end of a statement, to show that you have finished speaking, or to form a question or invite somebody to reply
- Thanks for your help, hey.
 - My new bike's nice, hey?
 
More Like This ExclamationsExclamations- aargh
 - ah
 - aha
 - ahchoo
 - ahem
 - aw
 - bah
 - boo
 - coo
 - d’oh
 - eek
 - eh
 - er
 - eww
 - gee
 - ha
 - hey
 - ho ho
 - ho-hum
 - hooray
 - huh
 - mm
 - oh
 - oho
 - oi
 - ooh
 - oops
 - ouch
 - ow
 - oy
 - pah
 - phew
 - psst
 - sh
 - tsk tsk
 - tut
 - ugh
 - uh
 - uh-oh
 - uh-uh
 - um
 - whoopee
 - whoops
 - woo hoo
 - wow
 - yay
 - yippee
 - yuck
 - yum
 
 
Word Originnatural exclamation: first recorded in Middle English.
Idioms 
what the hey! 
- (North American English, informal) used to say that something does not matter or that you do not care about it
- This is probably a bad idea, but what the hey!