Source : Webster's Revised Unabridged Dictionary (1913)

Emeritus \E*mer"i*tus\, a. [L., having served out his time, p.
   p. of emerere, emereri, to obtain by service, serve out one's
   term; e out + merere, mereri, to merit, earn, serve.]
   Honorably discharged from the performance of public duty on
   account of age, infirmity, or long and faithful services; --
   said of an officer of a college or pastor of a church.

Emeritus \E*mer"i*tus\, n.; pl. {Emeriti}. [L.]
   A veteran who has honorably completed his service.

Source : WordNet®

emeritus
     adj : honorably retired from assigned duties and retaining your
           title along with the additional title `emeritus' as in
           `professor emeritus'; `retired from assigned duties'
           need not imply that one is inactive [syn: {retired}]