1: Its a firm, small lettuce (3)
2: Unfathomable letters from Lamb, say (7)
3: Bride's outfit - a sort of shirt by Jean-Jacques? (9)
4: Hazardous emanation from river used by a crime boss (5)
7: Witty remark, for example, about constant batterer (7)
8: Some wear medals when carrying weapons (5)
11: However, you expect trouble at first (3)