The best replacement for undershirt is no undershirt.

The best alternatives to undershirt are rated as following:
★★★★★  no undershirt
★★★  tank top
★★  wife beater
  t-shirt
  training bra
  sleeveless

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

Other search terms related to undershirt and their ratings are:
★★★★★ polo
★★★★★ suit
★★★★★ button down
★★★★ white dress shirt
★★★★ v neck
★★★ henley
★★ button up
★★ dress shirt
★★ v neck sweater
★ flannel
polo shirt
You have in mind a companion for undershirt and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of undershirt in all years. Click on graph for more.
undershirt
no undershirt
tank top