The Collaborative International Dictionary of English v.0.48:

Inmate \In"mate`\ ([i^]n"m[=a]t`), n. [In + mate an associate.]
   One who lives in the same house or apartment with another; a
   fellow lodger; esp., one of the occupants of an asylum,
   hospital, or prison; by extension, one who occupies or lodges
   in any place or dwelling.
   [1913 Webster]

         So spake the enemy of mankind, inclos'd
         In serpent, inmate bad.                  --Milton.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Inmate \In"mate`\, a.
   Admitted as a dweller; resident; internal. [R.] "Inmate
   guests." --Milton.
   [1913 Webster]

WordNet (r) 3.0 (2006):

inmate
    n 1: one of several resident of a dwelling (especially someone
         confined to a prison or hospital)
    2: a patient who is residing in the hospital where he is being
       treated [syn: inpatient, inmate] [ant: outpatient]
    3: a person serving a sentence in a jail or prison [syn:
       convict, con, inmate, yard bird, yardbird]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "inmate":
   addressee, artist-in-residence, captive, case, convict, denizen,
   dweller, habitant, house detective, incumbent, inhabitant,
   inhabiter, inpatient, intern, lag, live-in maid, locum tenens,
   occupant, occupier, patient, prisoner, residencer, resident,
   resident physician, residentiary, resider, sojourner, tenant



Bouvier's Law Dictionary, Revised 6th Ed (1856):

INMATE. One who dwells in a part of another's house, the latter dwelling, at
the same time, in the said house. Kitch. 45, b; Com. Dig. Justices of the
Peace, B 85; 1 B. & Cr. 578; 8 E. C. L. R. 153; 2 Dowl. & Ry. 743; 8 B. &
Cr. 71; 15 E. C. L. R. 154; 2 Man. & Ry. 227; 9 B. & Cr. 176; 17 E. C. L.
R. 385; 4 Man. & Ry. 151; 2 Russ. on Cr. 937; 1 Deac. Cr. L. 185; 2 East,
P. Cr. 499, 505; 1 Leach's Cr. L. 90, 237, 427; Alcock's Registration Cases,
21; 1 Man. & Gra. 83; 39 E. C. L. R. 365. Vide Lodger.