He's off drinking with his mates...是什么意思？

He's off drinking with his mates...

他跟哥儿们出去喝酒了。

off

prep. 从…落下，离开，从…去掉，下班；adv. 离开，距，离，被取消，下班；adj. 不新鲜的，不能接受，不礼

例句
He eased his foot off the accelerator.
他松开了油门。

drinking

n. 喝饮料，喝酒；v. 喝（酒）( drink的现在分词 )，饮，喝酒，（尤指）酗酒；

例句
Wine is radioactive but few people stop drinking it on that account.
酒是有放射性的，可是很少有人因此而戒酒。

with

prep. 和，跟，随着，关于，和…一致；

例句
A waiter entered with a tray...
侍者端着托盘进来了。

his

pron. (he的所有格)他的，(he的物主代词)他的东西；det. 属于他的，用于名词前，自己的，指某人的，上帝的；

例句
He claimed that his parents had abandoned him...
他声称父母遗弃了他。

mates

n. [英]伙伴( mate的名词复数 )，同伴，（非正式）配偶，（熟练工人的）助手；

例句
The males guard their mates zealously.
雄性动物死死地守护着他们的配偶。