John Howard opening in Men From Warsaw showing many means of escape (9)
I believe the answer is:
loopholes
'men from warsaw showing many means of escape' is the definition.
I can't judge whether this defines the answer.
'john howard opening in' is the wordplay.
'john howard' becomes 'loops' (I can't explain this - if you can you should believe this answer much more).
'opening' becomes 'hole' (hole is a kind of opening).
'in' is an insertion indicator.
'loops' enclosing 'hole' is 'LOOPHOLES'.
Can you help me to learn more?
(Other definitions for loopholes that I've seen before include "gaps in wall" , "Escapes (legally!)" , "Legal ambiguities" , "Ways of evading rules, or slits in fort wall" , "Ambiguities that enable evasion of obligations" .)