### Clue: Start with money to maintain Anglesey's principal harbour (9)
### Answer: ENTERTAIN 
 ### Explanation: Definition: harbour
 ENTER(to start in/to join in, as in "he entered the work force as a temp" **plus**(with) TIN(slang for money) **containing**(to maintain) **1st letter of**(…'s principal) "Anglesey".
Defn: …/to keep/have in mind, as in "to entertain grudges from long ago".