ADJ.
infinite
VERB + TOUGHNESS
mask
TOUGHNESS + NOUN
depth, diplomacy, korean
PREP.
with
noun
The state of being tough.
A formidable difficulty.
noun — impressive difficulty
noun — the elasticity and hardness of a metal object
noun — the property of being big and strong
noun — enduring strength and energy
I still remember staring with fear at his face marked with candor and toughness.
Beyond his mask of toughness lies infinite depth.
Openness and toughness characterize Korean diplomacy.