Yes, STRIPPER is a Scrabble word!

Letter values in Scrabble US: S 1, T 1, R 1, I 1, P 3, P 3, E 1, R 1.

Is it a valid word?

STRIPPER is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

a chemical compound used to remove paint or varnish
a worker who strips the stems from moistened tobacco leaves and binds the leaves together into books
a performer who provides erotic entertainment by undressing to music
an oil well whose production has declined to less than ten barrels a day

Also: striptease artist, exotic dancer, stripper well.