His health condition precludes him from joining this mountain climbing trip.

precludes 是动词 preclude 的第三人称单数形式。preclude 由前缀 pre-（表示"在...之前"）和词根 clude（来自拉丁语 claudere，意为"关闭"）组成，字面意思是"预先关闭"，引申为"排除、阻止、使不可能"的意思。在句中表示"使某人无法做某事"的含义。