someone that is just a bag. It's not something that just happens over night, it's a very much a gradual process. A bag brain is someone that smokes shit loads of pot most days of the week and pretty much become dependent on it. If someone is a bag they're usually pretty chill to be with as they're calm people themselves.
'Philip has turned into such a bag brain!''
'Hey Colin, what do you say we try and get the bag to come and play football with us?'
'Hey Colin, what do you say we try and get the bag to come and play football with us?'
by bag brain July 16, 2014
by JJ Ephus August 12, 2005