### Clue: Hard thing to say to new visitor involving mixture of wit and hesitation (6-7)
### Answer: TONGUE-TWISTER 
 ### Explanation: Definition: Hard thing to say
A charade of TONGUETWIST, an envelope ('involving') of TWI, an anagram ('mixture of') of 'wit' in 'to' plus N ('new') plus GUEST ('visitor'); plus ER ('hesitation').