Q: what made sus chords so suspicious to give them their 'sus' name
A: it doesn't mean suspicious. it might mean 'suspended' which makes sense for sus4 but sus2 doesn't really feel suspended. if anything it feels more like a 'substitution'. i'd be ok with calling them sub4 and sub2. but no one calls it that, they call it sus2 and sus4, and that's fine with me. in that sense, sus2 and sus4 are words in their own right. looking back on this whole paragraph, actually i do admit this whole situation is kind of suspicious