Its a word of endearing. When your significant other says something along the lines of "I love you the most" you can say "well, I love you the mostest"
by Just_a_sensitive_Leo June 7, 2018
Get the Mostestmug. by Dante0930 November 12, 2019
Get the Mostestmug. by Boinkboy69 March 16, 2023
Get the Mostestermug. To have more of than anything else.
by Mr.Satisfied May 22, 2018
Get the Mostestermug. 
Dan told Alison he loves something the mostest which completely wrecked her “most” or someone tells you “I love you most “ and you respond “I love you mostest” you win
by Space Dani November 3, 2017
Get the Mostestmug.