DOUBLE TROUBLE

A policeman is known simply as a copper
Hopping on one leg you would be a hopper
That's when a thought occurred to me 
Both of these words have double pp

Putting in food ends up in your tummy
Especially nice if its cooked by mummy 
You will notice the end word has double mm
Strange to have these letters in them 

Grandma is often referred to as granny 
Some people I know call theirs nanny 
You may have spotted the double nn
Probably you're thinking double letters again

I will leave this poem for a game of chess
Don't want it to turn out to be a complete mess
Both these words end up with double ss
Another word does too I will let you guess