su·per·flu·id 
(s′pər-flĭd)
(s′pər-flĭd)n.
A fluid, such as liquid helium, that flows with little or no friction at temperatures close to absolute zero.
su′per·flu·idi·ty (-fl-ĭdĭ-tē) n.
- irrepressibleness
- irrepressibly
- irreproachability
- irreproachable
- irreproachableness
- irreproachably
- irresistibility
- irresistible
- irresistibleness
- irresistibly
- irresoluble
- irresolute
- irresolutely
- irresoluteness
- irresolution
- irresolvable
- irrespective of
- irrespirable
- irresponsibility
- irresponsible
- irresponsibleness
- irresponsibly
- irresponsive
- irresponsively
- irresponsiveness