Answer: toughnuttocrack

AnswerCrossword Clue
TOUGHNUTTOCRACK

Difficult task

TOUGHNUTTOCRACK

Poser

TOUGHNUTTOCRACK

Baffling problem

TOUGHNUTTOCRACK
One who's not easily convinced
TOUGHNUTTOCRACK
Baffler
TOUGHNUTTOCRACKIt's pretty challenging
TOUGHNUTTOCRACKSquirrel's headache?
TOUGHNUTTOCRACKHard problem
TOUGHNUTTOCRACKDifficulty
TOUGHNUTTOCRACKHeck of a puzzle