trialer

Noun

trialler (plural triallers)

1. A horse or a dog used for trialling.
   • Ch. Doony Bluebell, Fairholme Trusty, Type, and Typist, are notable, while the blue roan, Fairholme Rally, has attained conspicuous success as a field trialler, and at stud was responsible for transmitting length of head, then much needed in the breed, and sired innumerable winners.2013, H. S. Lloyd, The Popular Cocker Spaniel
2. A motorcycle specialized for trials events.
   • The 350 Alpina puts out two less horsepower than a 125 Elsinore. We got 18 horses on the pump. A 27mm Amal mixes. The bike isn’t as sluggardly as one might expect for a zooted-up trialer. One of ’em finished ninth in the 350 Expert at Hopetown last year. Mike Hannon must have ridden his bejeebers...1975 June, “Bultaco Alpina 350: Surefooted Sherpa Sibling”, in Dirt Bike, volume 5, number 6, Encino, Calif.: Hi-Torque Publications, Inc., page 28