asterisk
facemask, fallback, fastback, fatstock
funk
backtrack
The compound words backpack, backtalk, ballpark, bareback, bluebook, bodywork and bookmark will work. The word bobolink is not a compound word that meets the specifications.
amuck
alkylketalkevelkneelknellknollknurlkraalkrillskillskirlskullvakilyokel
squawkstreak
duck
bookmark ballpark bankbook bookwork backpack bareback basilisk beadwork bobolink backtalk
Kangaroos
knuckle
berserk?