1、You won't able to stuff him.应该是You won't be able to stuff him.
be able to do sth.有能力做某事.
won't = will not 将不会的意思.
所以你说的打败应该是指stuff了.但是stuff 原意没有打败别人的意思,可能是美国俚语里面的用法吧,俚语里stuff有：诓骗,作弄,欺负,丢掉,处理掉的意思.
2、In ability she towers over all the others in her class.
主句是：She towers over.她超过.
主语是：she 谓语是：tower.
all the others in her class 是宾语,就是她超过的对象.
in ability 是定语,就是她在哪个方面上超过.