Someone you know fairly well is giving off a new vibe, and you wouldn't be out of bounds if you considered it romantic! If the idea of taking this relationship into a new realm appeals to you, then make sure you encourage the way things are going. But if you want things to stay the same between the two of you, you need to be blunt and nip this thing in the bud. Be compassionate, but be firm about your boundaries. Rejection is never nice, but you can't lead them on.