It describes a player who uses an unfair weapon, the IW80. This weapon generates a large number of headshots, as it has little to no recoil while shooting fully automatic. Thus, the people who use it are I-dub-nubs.
It can be broken down quite simply as follows: i-dub-nub = IW80 newb. but, pronounced eye-duhb-nuhb.
This is a unique word in that, it was most certainly not created untill socom II came out in late 03, and in fact, it is rearley used since late 04, because most of the people that once used this word, have now banned this weapon from legitimate matches. A word that, although used alot for a period of 6 months, has begun to disappear! to find this rare word still being used, you might try some of the e-seals servers on socom 2, but, it may no longer exist!
"it is unfair to be on the terrorist team with all of these i-dub nubs on the seals. lets pick seals next map, well show them what it's like to be i-dub nubbed." used as a verb!