1. Grouse being docile when sloth returns. Answer: Complaint. Obviously this is compliant (docile) with the 'ai' transposed but I don't understand how sloth denotes the letters 'ai'?
2. After time hangman's victim gets a type of 18d (the answer to which is sack). Answer: Trellis. This is clearly time (T) with Ellis (the last woman hanged). But in what way is a trellis a type of sack?
3. Sailor from overseas takes small vehicle to city. Answer: Lascar. I'm assuming this is LA (city) next to car (small vehicle) but that leaves us with an extraneous 's'!
4. Quickly spread out after boss appears. Answer: Headlong. The boss is presumably 'head' but how can 'long' be synonymous with 'spread out'.
5. Distance between a pair of horses. Answer: Span