I first heard this in 2004 but apparently it's been around since 2002. It means: wanting something really badly; yearning; craving; to be a fiend for/of; a corrupted version of the word “fiend”, often used in the trying-to-quit, or broke (as in no money), addiction community.

feening - to want something badly, to have a craving.

(this quality word has been arround since early 90's from the jodeci, wayne marshall era or music)

Feenin' Meaning a craving or an urge about something most commonly associated with mens craving for women

(I first heard it in college in the early 90s.)

Feeling withdrawal symptoms from the lack of something, such as nicotine.

To contain a strong desire for something that satisfies something deep inside, typically a bad habit. Usually tends to be either drugs, cigarettes or chinese food.

Used by people too dumb to know the word is actually "fiending." See fiending.

to over exaggerate over something.
to be completely obssessed with something.