Definition of off-speed in English:

off-speed

adjective

  • Slower than expected.

    • ‘He used his fastball to set up his off-speed pitches.’
    • ‘In two-strike counts, he looks for off-speed pitches away.’
    • ‘Colon was expected to mix in off-speed pitches, but he has been trying to get by with average heat.’
    • ‘Some pitchers have found success by throwing him off-speed pitches inside, but they risk disaster if they don't throw it far enough inside.’
    • ‘Growth comes from learning an off-speed slider during spring training and having the guts to throw it in June.’