\Ir`re*solv"a*ble\, a. [Pref. ir- not + resolvable.
Cf. {Irresoluble}.]
Incapable of being resolved; not separable into component
parts.

{Irresolvable nebul[ae]} (Astron.), nebul[ae] of a cloudlike
   appearance, which have not yet been resolved by the
   telescope into stars.