Usage patterns
〈数〉勝〈数〉敗X wins and Y losses (a win-loss record)
This season the record was 10 wins and 5 losses.
敗を喫するto suffer a defeat
They suffered a heavy defeat against the powerhouse team.
〈数〉敗目the nth loss (in a series)
That's the third loss of the season now.
Expressions
驕兵必敗pride comes before a fall; an arrogant army is bound to lose 敗軍の将は兵を語らずdon't be a sore loser; don't make excuses for your failures; a defeated general should not talk of strategy