restrained
re-strained
adjective
Showing controlled emotion or behaviour; not excessive, flamboyant, or extravagant.
"Her restrained elegance was admired by all."
Thesaurus
Synonyms: cautious, guarded, unexpansive, subdued, low-key, close, low-keyed, undemonstrative, reticent, unemotional, unpretending, unostentatious
Antonyms: unrestrained