ufo

noun 0.818

flying saucer

noun 0.671

ufology

noun 0.618

alien abduction

noun 0.578

unknown

noun 0.571

unfamiliar

noun 0.569

mystery ship

noun 0.562

alien

noun 0.545

flying bomb

noun 0.537

celestial object

noun 0.530

spaceship

noun 0.517

airplane

noun 0.513

space vehicle

noun 0.509

flying fish

noun 0.506

aircraft

noun 0.506

outer space

noun 0.505

flying officer

noun 0.504

unseen

noun 0.502

unusual

noun 0.502