### Clue: A man in a cap coming back north on a long waterway (6,5)
### Answer: PANAMA CANAL 
 ### Explanation: Definition: waterway
 **Reversal of**(coming back) [ A MAN **contained in**(in) A CAP ] + N(abbrev. for "north") **plus**(on) A + L(abbrev. for "long", denoting a size longer than regular, for suits and coats for taller people ].