In british a hobknocker is a person who runs in the streets and hits people in their balls, or a person who hits people in the face with his balls. Used for swearing meaning a person who is a way too much annoying and stuff.
-He always texts me and he won't leave me alone!
-Ohhh gurl, such a hobknocker dat nigga is.
It is a made up word from the show iCarly. Wade Collins uses it to describe Freddy, Carly, Sam and Spencer. The writers of the show try to keep it a mystery but there is alot of speculation in the fanbase. The Merrian-Webster dictionary defines "hob" as a synonym for mischief or something illegal. Therefore, if it's gross AND illegal it most likely is one who is a necrophiliac or one who indulges in incest. However, judging by iCarly's target demographic of 10-15 year olds, it probably means incest since negrophilia is usually related to gross-er matters. Many fans believe that it may mean a prostitute; however, they forget that they replace "whore" with "skunkbag" just the way they replace "dipshit" with "dipwad."