教练告诫队员们不要有消极的态度，认为比赛还没开始就已经输了。

The coach warned the team against adopting a defeatist attitude, thinking they'd already lost before the game even started.

defeatist 是由名词 defeat（失败）加上后缀 -ist 构成的名词或形容词。defeat 意思是"失败"，后缀 -ist 表示"持有某种观点或态度的人"或"具有某种特性的"。 defeatist 作为名词指"失败主义者"，作为形容词表示"消极的、认输的"，形容一种认为失败不可避免的态度。