6 Mistake (7)
7 Ease (5)
9 Move very hastily (4)
10 Greenish blue (10)
11 Thread (8)
13 Relating to the iris of the eye (6)
15 Dirty air (4)
17 Wife of Odin (Norse mythology) (5)
18 Wooden pins (4)
19 A parasitic marine protozoa (6)
20 Educated (8)
23 Bottomless (10)
26 "Born Free" lionness (4)
27 Mar (5)
28 Imp (7)
Down
1 Square (10)
2 Envisage (6)
3 A language of Pakistan and India (4)
4 Slouching (8)
5 Agitate (4)
6 Italian lawn bowling (5)
8 Expressing a totally negative opinion (7)
12 Threesomes (5)
14 In an inappropriate manner (10)
16 Not reptiles (7)
17 Shard (8)
21 Snake sounds (6)
22 A red fluorescent dye (5)
24 Fraud (4)
25 They come from chickens (4)