Synonym word of flack:

affliction, ax to grind, beef, bellyache, big stink,blast,case,cross,damage,distress,flack,grief, grouse,hardship,holler, hoo-ha,howl,injury,injustice, jeremiad,kick,knock,objection,outrage,pain, pain in the neck, rap,resentment,rigor,roar,rumble,sorrow,