1. Physically toughened
   - tough 
2. Made hard or flexible or resilient especially by heat treatment
   - tempered, treated, hardened

1. Make tough or tougher
   "This experience will toughen her"

See also: callous, calloused, curable, enured, experienced, experient, hardened, inured, rugged, strong, sunbaked, thickened, weather-beaten

Type of: strengthen

• cirio
• cirque
• cirrhosis
• cirrhosis of the liver
• cirrhotic
• cirrhus
• cirriped
• cirripede
• Cirripedia
• cirrocumulus
• cirrocumulus cloud
• cirrose
• cirrostratus
• cirrostratus cloud
• cirrus
• cirrus cloud
• Cirsium
• Cirsium arvense
• Cirsium discolor
• Cirsium eriophorum
• Cirsium flodmanii
• Cirsium helenioides
• Cirsium heterophylum
• Cirsium lanceolatum
• Cirsium rivulare