### Clue: Start to swear briefly after lout becomes mischievous creature (9)
### Answer: HOBGOBLIN 
 ### Explanation: Definition: mischievous creature
 I can't satisfactorily explain the wordplay.  Is it: [ GO(to start;to set out, say, on a journey) + "blind"(I presume from "eff and blind";to use swear words, OR from "swear blind";to state assertively) **minus its last letter**(briefly) ] **placed below**(after, in a down clue) HOB(itself short for "hobgoblin";a mischievous creature – but an understatement, to say the least, if used to describe a lout).