When I am on campus I carry a case peanut, because our campus limit is 2 1/2" but at 2 1/8" is it slightly over your limit. OTH, the peanut is so friendly--especially the yellow delrin--that non-knife people think it is cute and/or old fashioned. It is more like walking a puppy in the park than "pulling a knife." Also, without making this a peanut appreciation thread, it does disappear in the pocket and punches way above it's weight (1.2 Oz).
Staying below 2" I would suggest looking at a SAK manager or midnight manager (1 1/2" blade). The Manager is one of my all time favorites for high functionality in a small friendly lightweight package (1 Oz). The surprising thing is that the tools work so well and I actually used all the tools within a short time of getting it (well maybe not the tweezers, but that pen came in handy almost immediately). No matter what else I am carrying, I have this one with me.
Another friendly option if you are willing to go up in bulk and weight (2 Oz), is a Leatherman Squirt PS4. You get needle nose pliers along with most of the functionality of the Manager except pen (and/or light) and a little longer blade (1 5/8").