An individual that consumes cardboard on a daily basis solely for the purpose of filling their dietry and nutritional needs. Normally someone who can not afford to buy anything of real sustinence.
Josh John went to Greggs and bought some chicken goujons (well, well, well), instead he deciced to eat the box, what a cardboard muncher.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.