toughen What is the Definition of toughen?Verb:make tough or tougher Other meanings of toughen (synonyms, cognates). ENRU toughen закалять Frequently viewed: keep in a sentenceshake in a sentencenearly definitiondefinition of alarmdefinition of duebehind definitionbrand meaningtaste definitionvast definitiondefinition of deltaactive definitioninstinct 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