The project manager off-loaded some tasks to his assistant.

off-loaded 是动词短语 off-load 的过去式形式。off-load 由前缀 off-（表示"离开、去除"）和动词 load（装载）组成，字面意思是"卸下装载"，引申为"转移、移交（任务或责任）"的意思。