If you twirl, you turn around and around quickly, for example when you are dancing. Several hundred people twirl around the ballroom dance floor. = whirl
If you twirl something such as your hair, you twist it around your finger. Sarah lifted her hand and started twirling a strand of hair. to turn around and around or make something do this twirl around/round (Perhaps from a language)
If you twirl something or if it twirls, it turns around and around with a smooth, fairly fast movement. Bonnie twirled her empty glass in her fingers All around me leaves twirl to the ground
the act of rotating rapidly; "he gave the crank a spin"; "it broke off after much twisting"