### Clue: Mast's up with difficulty? Boatman's apt to take it for granted (10)
### Answer: ASSUMPTIVE 
 ### Explanation: Definition: apt to take it for granted
 **Anagram of**(… with difficulty) MAST'S UP + I'VE(contraction of "I have";Boatman has;Boatman's, with setter using the self-referential pronoun).