Archimago's name suggests two different things, which is fitting for a guy who is defined by his deceptiveness and duality (yep, it's no coincidence that he and Duessa are BFF). 'Archimago' suggests an 'arch-magician,' which is certainly true since he is constantly concocting mean and troublesome spells. His name also suggests a 'creator' (same root as 'architect') or 'images' ('imago'), which speaks to his irritating habit of producing false visions and deceptive images.
The biggest of these false deceptions is the construction of the false Una, which tricks Redcrosse into thinking the real Una is unfaithful. In general, though, we almost always encounter Archimago in some kind of disguise, sending well-meaning knights off into serious danger. Like Busirane and Acrasia, Archimago is one of the villains through whom Spenser explores the dangers of making images and producing art.