Related Clues:

• Snooker on the green?
• Snooker, of course, in the old days
• It's about setter's rising drug problem of old, of course
• Pen note to European leader in awkward situation
• Month without unexpected burst to get in the way
• Block scurrilous items about celebrity's bottom
• Stop progress, arrested by frosty mien
• Impede - block
• Thwart (as once was possible on the green)
• Prevent (by getting in the way)
• Situation from which it is almost impossible to proceed
• Thwart — block — my site (anag)
• Obstruction (originally at golf)
• Prevent progress of one coming between me and mess that's ahead
• Where to find 12 (and Arachne sousing herself in Scotch)