RichThesaurus
impervious (to)
vs
unruffled
impervious (to)
unruffled
adj
Not ruffled or tousled.
Calm, not ruffled, serene, at peace, unbothered.
How often have the words
impervious (to)
and
unruffled
occurred in a corpus of books?
(source:
Google Ngram Viewer
)