A "thumb wrestler" is a person who acts tough through text message. Using their thumbs to input words and threaten or intimidate other people.
I was on Instagram yesterday and I added a comment to someone's pic when all of a sudden this "Thumb Wrestler" got upset and tried to pick a fight with me.
by MrSilkySensations August 21, 2014
In the context of an online dating profile this means a guy with a thumb sized penis that masturbates constantly
He claims to be a “world champion thumb wrestler”
by Lzeb October 3, 2019