toughen What is the Definition of toughen?Verb:make tough or tougher Other meanings of toughen (synonyms, cognates). ENRU toughen закалять Frequently viewed: slippery meaningindices definitiondefinition of yourselfdefinition of infrastructurewish meaningcount meaningware in a sentenceconcur meaningguess meaningrecord meaningpop in a sentencedefinition of resolve 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