具体解释要看语境
big没有什异议 mean就不好说了
可以翻译成他们块头都很大而且非常吝啬
mean
/ miːn; min/ adj (-er,-est)
(with sth) ungenerous; selfish (esp with money) 吝啬的; 自私的（尤指金钱方面）:be very mean with money 对钱十分吝啬 * She's too mean to make a donation.她很小气,不肯捐款.
(to sb) (of people or their behaviour) unworthy; unkind （指人或人的行为）卑鄙的,不善良的:That was a mean trick!那是卑鄙的伎俩!* It was mean of you to eat all the food.你把东西全吃光了,你可太坏了.* Don't be so mean to your little brother!别对你弟弟那麽刻薄!* I feel rather mean for not helping more.我未能多帮忙,十分抱歉.
(esp US) nasty; vicious 刻毒的; 邪恶的:A rattlesnake is a really mean creature.响尾蛇是很凶的动物.* He looks like a mean character.他看上去不似善类.
poor in appearance,quality,etc; shabby-looking 难看的; 劣质的; 简陋的; 破旧的:the mean little houses where the poorest people live 最穷苦的人赖以栖身的破败小屋.
(esp of the understanding or abilities) inferior （尤指理解力或能力）低劣的,平庸的:This should be clear even to the meanest intelligence.就是对智 力最差的人来说,这也应当是很清楚的.
(dated 旧) of humble birth or low social rank 出身微贱的; 社会地位低下的:The meanest labourer has the same rights as the richest landowner.最贫贱的劳动者享有和最富的地主同样的权利.
(infml approv 口,褒) very skilful,effective,etc 熟练的; 有效的; 出色的:a mean golfer,chess-player,etc 出色的高尔夫球手、 国际象棋选手等 * a new tennis champion with a mean service 发球刁钻的新网球冠军.