In the context of the forums, the rootword of "necropost," which is "post," is most accurately defined as "a message published on a website." The prefix of the word, "necro-" most nearly means "dead." As such, the appropriate definition for a "necropost" (which can function as both a noun and a verb) would be "(v) the act of publishing a message on a website in a dead topic" or "(n) a message published on a website in a dead topic."
"dude... you justtotally necroposted"
"lol what?"
"YOU POSTED IN A TOPIC FROM LIKE, 4 MONTHS AGO, LOLOLOLOL!"
West Midlands slang word for rockers, bikers, greasers etc. In the late 1980s it was used by the UK music press to refer to a specific scene centered around the bands Pop Will Eat Itself and Crazyhead. The term never found favour with readers of 'the inkies' (Sounds, Melody Maker and the still extant NME) and was soon dropped. Now often used in predominantly working-class areas of the midlands and the north to mean someone who listens to rock-derived music and/or dresses in a manner that suggests they affiliate themselves with rock music of some kind.
Some grebo passed with Sabbath playing on his stereo.
The Poppies are at no. 17? God, a grebo band in the charts!
They're playing nu-metal now, bloody grebos!