The Collaborative International Dictionary of English v.0.48:

Paresis \Par"e*sis\, n. [NL., from Gr. pa`resis, fr. parie`nai
   to let go; para` from + "ie`nai to send.] (Med.)
   Incomplete paralysis, affecting motion but not sensation.
   [1913 Webster]

WordNet (r) 3.0 (2006):

paresis
    n 1: a slight or partial paralysis

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "paresis":
   French disease, Spanish pox, VD, acquired syphilis, apoplexy,
   balanitis gangrenosa, catalepsy, cataplexy, cerebral tabes,
   chancre, chancroid, clap, claps, climatic bubo,
   congenital syphilis, constitutional syphilis, diplegia, dose,
   dose of clap, fifth venereal disease, general paresis, gonorrhea,
   granuloma inguinale, granuloma venereum, great pox, hard chancre,
   hemiplegia, infantile paralysis, latent syphilis, locomotor ataxia,
   morbus Gallicus, palsy, paralysis, paralytic dementia, paraplegia,
   polio, poliomyelitis, pox, pudendal ulcer, sensory paralysis,
   simple chancre, social disease, soft chancre, stroke, syph,
   syphilis, syphilitic meningoencephalitis, tabes, tabes dorsales,
   tertiary syphilis, tropical bubo, venereal disease