All answers contain letters from the word CELEBRATION
1.The part of the body below the waist - 4
2.The part of a lock the key presses when turned that causes the bolt to slide out - 5
3.A thick brown sticky liquid - 7
4.A small private room - 7
Thank you all for taking the time to respond. Treacle is spot on and so obvious now! I also thought tenon as locks do have a mortice but thought that was more carpentry related. Loin is good also so thanks again.