1. refractory   bony or having bones.   iridescent or displaying rainbow-like colors.   suitable for drinking.   stubborn or rebellious.   Hint Dica Meio-a-meio   2. thermal   inflexible or strict.   pertaining to heat.   unnecessarily repetitious.   sound or logically convincing.   Dica Meio-a-meio   3. resonant   echoing or resounding.   with only one color.   muddy or not clear.   caustic or sharp in taste or smell.   Dica Meio-a-meio   4. permeable   penetrable or allowing fluids to pass through.   with only one color.   pertaining to memory or memory-aid.   echoing or resounding.   Dica Meio-a-meio