Synonyms of toughen

toughen

verb

ˈtə-fən 

1

as in to strengthen

to increase the ability of (as a muscle) to exert physical force

weight lifting will help toughen those flabby muscles of yours

Synonyms & Similar Words

• strengthen
• harden
• fortify
• beef (up)
• temper
• invigorate
• anneal
• tone (up)
• energize
• vitalize
• firm (up)
• restrengthen

Antonyms & Near Antonyms

• weaken
• hurt
• impair
• cripple
• injure
• paralyze
• harm
• damage
• debilitate
• enervate
• enfeeble
• undermine
• incapacitate
• break down
• wear out
• undercut
• sap

2

as in to harden

to make able to withstand physical hardship, strain, or exposure

hiking every morning through snow and ice toughened him considerably

Synonyms & Similar Words

• strengthen
• harden
• fortify
• adjust
• steel
• inure
• bolster
• adapt
• season
• reinforce
• acclimate
• indurate
• enforce
• invigorate
• temper
• brace
• acclimatize
• vitalize
• anneal
• immunize
• buttress
• accustom
• boost
• condition
• habituate
• break in
• support
• prop (up)
• train
• naturalize
• forearm
• limber (up)

Antonyms & Near Antonyms

• soften
• weaken
• exhaust
• emasculate
• sap
• cripple
• incapacitate
• hamstring
• sensitize
• enfeeble
• enervate
• debilitate

3

as in to stiffen

to make more harsh, uncompromising, or severe

attempts to toughen conditions under which waivers from military service would be permitted

Synonyms & Similar Words

• strengthen
• stiffen
• harden
• harshen

Antonyms & Near Antonyms

• ease
• lessen
• soften
• ameliorate
• moderate

Example Sentences

Recent Examples of toughen

Pan, a pediatrician, made national headlines during his time in Legislature for leading the state’s efforts to toughen school vaccine requirements. — Mathew Miranda june 23, Sacbee.com, 23 June 2026

Through the efforts of the foundation, the Florida Legislature passed a law in 2025 that toughens penalties for boating crashes that end in serious injury, for providing misleading statements to law enforcement during a boat-crash investigation, and boating under the influence of alcohol or drugs. — Grethel Aguila, Miami Herald, 23 June 2026

Britain has increasingly toughened its approach to tech firms, urging or forcing them to adapt their algorithms and, most recently, prevent children from circulating ​nude images taken on mobile phones. — Paul Sandle, USA Today, 16 June 2026

Britain has increasingly toughened its approach to tech companies in recent years, urging or forcing them to impose age verification, adapt their algorithms and, most recently, prevent children from circulating nude images taken on mobile phones. — Reuters, CNN Money, 15 June 2026