To understand what it means, we need more context. Could you please provide more information? For example:
* Where did you encounter this word? (e.g., online forum, conversation, song lyrics)
* What was the context of the word? (e.g., what was the conversation about?)
* What is the approximate age and location of the person who used it?
With more information, I can try to figure out what "pleh" might mean.