effere effete efreet efter- errett fekete ferfer ferrer ferret fertee ferter fetter frefre frette fterer fterre k-tree keefer keeffe keeker kereft kerker kertee ketter krefft kreker kretek r-tree reefer reeffe reeker refeet refeff refert refete refret refter reteer reteet retere retree retret retter t-tree teetee teeter terete terrer terret terter tertre tetete tetter treete trefet trefte treker tretee trette