Compare knuckleball with other words:
knuckleball vs. mobile
knuckleball vs. sinker
bug vs. knuckleball
dancer vs. knuckleball
floater vs. knuckleball
knuckleball vs. plate
knuckleball vs. rotation
knuckleball vs. pitch
knuckleball vs. slider
fastball vs. knuckleball
knuckle vs. knuckleball