The coach's speech was very motivating, making us all eager to win the game.

motivating 是动词 motivate 的现在分词形式，motivate 由词根 mot（移动）和后缀 -ate（使...）组成，意思是"激励、鼓舞"。现在分词形式 motivating 在这里作形容词用，表示"激励人心的、鼓舞士气的"。