Initially 'low' (eg: a low), Someone at a lower level.
Someone that lacks skills or
brain or
XP or sense of humour or
whatever.
The suffix 'zor' is used as usual to reinforce the meaning.
hohoho you're still lvl 57, you stupid lowZor !?
omg look at that lowzor, he still wears
green items !
l0wz0rs !1!!11
Why dya break that
sheep ffs !?? 'cause I'm low'sir..