Softball rhymes with:
basketball, fastball, football, meatball, racquetball, spitball, arenaball, basketball, blackball, butterball, cannonball, eyeball, fastball, fireball, football, handball, hardball, meatball, mothball, oddball, pinball, powerball, racquetball, screwball, snowball, spaceball, spitball, stickball, tidball, trackball, volleyball
Softball sounds like:
spitball, spiteful, susceptible