1: Bounder beheaded by slippery swimmer (3)
2: Mineral springs start to moderate involuntary muscular contraction (5)
3: Places and composition? (9)
4: Agree to make Lucifer wicked? (3)
5: Language making a comeback in modern Italy (5)
8: Run around near a stadium (5)
9: Erin's heir is hardly content (5)
11: Neil lost a letter and ended up with nothing (3)
13: Oxygen is pretty amusing. (3)