A young adult male who likes to smoke marijuana in mass quantities then proceeds to fuck someone's older sister, and then comes downstairs and proclaims himself "uncle eddie".
Younger Sister: Whatchya doin?!
Young AdultMale: I'm your new uncle eddie!
Older male, usually in his 40s, who gives off a creepy uncle vibe, hence the term "Uncle Eddie". Will take female friends to Vegas, but is often mistaken as their 'fun' loving uncle.
Nickname you give someone who you do not trust with younger children.