What does toughen mean?
Toughen means (transitive) To make tough..
/ˈtʌfən/ · verb
(transitive) To make tough..
The new training program is designed to toughen the athletes.
A cold shower every morning will toughen your skin.
Although the Office of Rail and Road (ORR) had toughened its stance on new third rail electrification, gaining approval for short sections of third rail to charge the batteries could be more straightforward.
Choose a synonym only when it preserves the intended meaning, tone, and grammar of the full sentence.
Toughen means (transitive) To make tough..
The closest synonym depends on the sentence and intended sense.
The opposite depends on the specific sense.
The new training program is designed to toughen the athletes.
FreeDictionaryAPI.com / Wiktionary · Original source · CC BY-SA 4.0
Dictionary data is provided by FreeDictionaryAPI.com and sourced from Wiktionary under its stated license.