re·frac·to·ry / riˈfraktərē/ • adj. formal 1. stubborn or unmanageable: his refractory pony.2. resistant to a process or stimulus: some granules are refractory to secretory stimuli. ∎  Med. (of a person, illness, or diseased tissue) not yielding to treatment: healing of previously refractory ulcers. ∎  rare Med. (of a person or animal) resistant to infection. ∎  technical (of a substance) resistant to heat; hard to melt or fuse.• n. (pl. -ries) technical a substance that is resistant to heat.DERIVATIVES: re·frac·to·ri·ness n.

refractory (ri-frakt-er-i) adj. unresponsive: applied to a condition that fails to respond satisfactorily to a given treatment.