/ ˈluːzə(r); NAmE / noun
1.
a person who is defeated in a competition :
winners and losers
He's a good / bad loser (= he accepts defeat well / badly) .
2.
a person who is regularly unsuccessful, especially when you have a low opinion of them :
She's one of life's losers.
He's a born loser .
3.
a person who suffers because of a particular action, decision, etc. :
The real losers in all of this are the students.