shop around means compare price (e.g. I want to shop around a little before I decide on these boots.)
show off means try to impress people with your ability, your knowledge etc. (e.g. Look at that boy on the bike riding with no hands. He’s just showing off)
show up (or turn up) means arrange, appear
shut down (or close down) means stop doing business
sit down/ bend down/ lie down (e.g. I bent down to tie my shoelace)
sleep over means stay somewhere for the night (e.g. You should sleep over tonight if the weather is too bad to drive home.)
slow down means go more slowly (e.g. You’re driving too fast. Slow down)