Extol
To praise highly
Extradite
To turn a prisoner over to the jurisdiction of another country or state where the crime was allegedly committed
Extraneous
Not belonging
Extrovert
One who is outgoing, friendly
Exult
To rejoice over a success or victory
Feasible
Reasonable, likely
Fickle
Likely to change without reason
Formidable
Hard to overcome or deal with
Frugal
Not wasteful
Expound
To explain