TOUGHEN
Meaning of TOUGHEN in English
v. Function: verb
Synonyms: HARDEN 2, acclimate, acclimatize, climatize, season
Related Words: develop, strengthen
Antonyms: weaken
Merriam Webster.
Collegiate thesaurus English dictionary.
Английский энциклопедический толковый словарь тезауруса.
2012