Related Clues:

• Constrain
• Restrict
• Squeeze
• Screw up
• Take up the slack
• Stiffen
• Make more secure
• Constrict
• Use a clamp, say
• Make more taut
• Secure, in a way
• Turn a vise handle clockwise
• Do this to your belt to economise (7)
• Turn, a screw say
• Perhaps get drunk, but don't get loose