The best replacement for thinning is balding.

The best alternatives to thinning are rated as following:
★★★★★  balding
★★★  cowlick
★★  bald
★★  fading
★★  hair loss
★  loss
★  mpb
  pruning
  thixotropic
  layering
  texturizing
  receding

Your alternative for thinning is not listed? Suggest!
Speaking about thinning, one probably shouldn't forget about shedding.

Other search terms related to thinning and their ratings are:
★★★★★ shedding
★★★★ receding
★★★ hair loss
You have in mind a companion for thinning and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of thinning in all years. Click on graph for more.
thinning
balding
cowlick