To steal another site's bandwidth, usually by showing a picture directly instead of linking to the site. Leechers can normally expect their file to be swapped for something horrifying.
Poster #1: YEEEEEEARRRGH!!!! That picture I posted changed into the Harlequin Fetus!

Poster #2: That'll teach you not to leech, fag.
by Freddy November 16, 2003
a person who downloads excessively from the internet, regardless of the content, they need to keep their connection fully utilised 24/7...
OMFG, he leeched like 500 gigs last month!
Comindico sucks cause there are so many fuckin' leechers!
by mr a March 11, 2004
Term used to describe a woman who is pushing 40 and still lives at home with her parents and sucks the life out of them.
That loser Teresa is a middle aged leech who still lives with her parents.
by Freethewhale July 19, 2010
Type of behaviour that constitues extreme insults, emotional and sexual harrassment in the workplace. The 'Leech' will often blame his own dispicable behaviour upon other colleagues, and has NO FEAR of Human Resources or indeed his own conscious.
That Andy is such a leech - I hear Anna fell over the other day and he groped her on the way down!
by Leech-Victim March 4, 2009
A. Someone who solicits pity so that anyone will give them help and then takes advantage.

B. Someone who appears as if they have everything under control if you “just help them until they find a job” and then when they do they pay you back a portion to disguise what they are until they loose there job or quit because of “harsh work environments” to regain pity from the person they are leeching from.
Tommy is such a leech! He is staying with me until he gets a job but he doesn’t look like he is getting one any time soon.”
by Amber Campbell August 19, 2018
A person who leeches onto another for monitary or sexual pleasure
Sean 'tits' Seggie sucking Ryan Zwicker's cock
by sean 'tits' seggie February 7, 2003