toughen What is the Definition of toughen?Verb:make tough or tougher Other meanings of toughen (synonyms, cognates). ENRU toughen закалять Frequently viewed: definition of doubtdefinition of deploytelephone meaningappear definitioncareful definitioncertainly in a sentencedefinition of digitalbrought meaningshopping meaningreal meaningdefinition of coffeething meaning A B C D E F G H I J K L M N O P Q R S T U V W X Y Z