Answer:

ABSTRUSE

Answer	Crossword Clue
ABSTRUSE	Hard to grasp
ABSTRUSE	Clear as mud
ABSTRUSE	Esoteric

ABSTRUSE	Recondite
ABSTRUSE	Deep
ABSTRUSE	Hard to understand

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.