Is this rube?

Oh! what a strange prompt today

all my thoughts have gone ashtray

didn’t know the meaning of rube

my vocabulary is going to droop

is it the cube fallen in a river

the idea itself gives me shiver

is the the railways called tube

No! that is a literally bad rube

is it that rust preventing lube

Ah! that is quite a slippery rube

Rube rube rube!

forcing me to snoop