bear - a man with a beard or van Dyke, typically with a hairy chest and body and a stocky or heavyset build; often older (or older looking) and displaying a masculine appearance and mannerisms.
Specifically:
polar bear - an older guy with white or grey fur/beard.

A phrase to describe someone who is cognitively degenerating. Synonym of "going off the deep end". Can have varying degrees of severity.

Reference to the song "Hey You" by Pink Floyd. The line "and the worms ate into his brain" makes no sense in an otherwise linear and literal narration throughout the lyrics.

A short, generic name used in a way such as "John Doe", but rather then to describe a generic person it is used to describe a generic, unemployed, cheap and constantly drunk person. Sometimes abbreviated simply as DL.

A confused but determined male.