Eclectic -- from diverse sources (adj)

 Efface -- to erase (verb)

 Elusive -- difficult to catch or define (adj)

 Empirical -- based on observation and experimentation (adj)

 Enigma -- a puzzle or mystery  (noun)

  Epiphany -- sudden realization (noun)

 Equanimity -- calmness (noun)

 Erudite -- scholarly; intelligent; showing great knowledge (adj)

 Excavate -- unearth; to dig up (verb)

 Exhort -- encourage (verb) 

 Exorbitant -- too expensive (adj)

 Expedient -- convenient; practical (adj)

 Expose -- to make visible by uncovering (verb)

 Extol -- to praise and worship (verb)

 Facile -- easy; superficial; effortless (adj)

 Fallacious -- deceitful; incorrect (adj) 

 Fanaticism -- excessive enthusiasm (noun) 

 Fastidious -- careful; exacting (adj)

 Fathom -- to understand; to comprehend (verb) 

 Felicitous -- well-suited; happy and content (adj) 

  Finesse -- tact; elegance (noun) 

 Flagrant -- evident; obvious (adj) 

 Flippant -- disrespectful; cursory (adj) 

 Flummox -- confuse; bewilder  (verb)