Yes, plop is a Scrabble word!
...and is worth 8 points in Scrabble, and 11 points in Words with Friends
plop
Adverb
1. With a short hollow thud
Verb
1. Drop something with a plopping sound
2. Drop with the sound of something falling into water
3. Set (something or oneself) down with or as if with a noise
Noun
1. The noise of a rounded object dropping into a liquid without a splash
What Scrabble words can I make with the letters in plop?
3 Letter Words
2 Letter Words