1. A material that hardens when heated and cannot be remolded
   - thermosetting resin

Type of: plastic

• unrewarding
• unrhetorical
• unrhymed
• unrhythmic
• unrhythmical
• unrifled
• unrig
• unrigged
• unrighteous
• unrighteously
• unrighteousness
• unrimed
• unrip
• unripe
• unripened
• unrivaled
• unrivalled
• unroll
• unromantic
• unromantically
• unroofed
• unrouged
• unrounded
• unruffled
• unruliness