Extremely Difficult or Challenging; Devious

This page is the CodyCross answer for the clue below from Underground Worlds, Group 2166, Puzzle 1 (Peridot and Pyrite).

Question is: Extremely Difficult or Challenging; Devious

and the answer is: FIENDISH

Word Meaning:

FIENDISH — Sinister; evil; like a fiend.

Definitions from Wiktionary.

Extremely Difficult Or Challenging; Devious - Underground Worlds CodyCross Answers | CodyCross Solutions