Five letter words with__ack in them

Aback,Snack,Knack,Black,Stack,Plack,Chack,Thack,Shack,Crack,Whack,Smack,Flack,Alack,Spack,Kiack,Brack,Swack,Kyack,Clack,Track,Quack,Drack,Wrack,Slack,Frack