its the newest way to call something cool instead of using old phrases like "thats ledgendary"
Amar: Yo chris i just ate a green crisp... i didnt even friggin puke!
chris: AMAR!! Thats beastidge!
Amar: beastidge (he doesnt know anyhting amar)
chris: yea beastidge i learnt it on urban dictionary its a rocking word, so start using it or i amy resort to peer pressure!