pneumatic /n(j)uːˈmæ.tɪk/adjective 6noun 2forms 3 adjective6 •Of, relating to, or resembling air or other gases •Powered by, or filled with, compressed air •Of or relating to pneumatics •well-rounded; full-breasted; bouncyHer almost pneumatic bust tightened itself, and she was quite prepared to say uncharitable things, as she saw Felicia enter. — 1899 •Having cavities filled with airpneumatic cells or bones •Spiritual; of or relating to the pneuma noun2 •In the gnostic theologian Valentinus' triadic grouping of man, the highest type; a person focused on spiritual reality (the other two being hylic and psychic). •(old-fashioned) A vehicle, such as a bicycle, whose wheels are fitted with pneumatic tyres. formspneumatics · more pneumatic · most pneumatic