The best replacement for stallion is gelding.

The best alternatives to stallion are rated as following:
★★★★★  gelding
★★★★★  mare
★★★★  mustang
★★★  stud
★★  surgeon
★★  horse
★★  super power
★  steed
★  thoroughbred
★  lakota
★  chinook
  donkey
  proton power
  war horse
  stallion
  filly

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

Other search terms related to stallion and their ratings are:
★★★★★ mare
★★★★ distinction
★★★ approval
★ all probability
★ gelding
mare in heat
You have in mind a companion for stallion and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of stallion in all years. Click on graph for more.
stallion
gelding
mare