The Collaborative International Dictionary of English v.0.48:

Misusage \Mis*us"age\ (m[i^]s*[=u]z"[asl]j), n. [Cf. F.
   m['e]susage.]
   Bad treatment; abuse. --Spenser.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

54 Moby Thesaurus words for "misusage":
   Irish bull, abuse, abuse of office, anacoluthon, antiphrasis,
   barbarism, befoulment, bull, catachresis, conversion,
   corrupt administration, corruption, debasement, defalcation,
   defilement, desecration, diversion, embezzlement, fluff,
   folk etymology, fouling, grammatical error, hypercorrection,
   hyperform, infelicity, maladministration, malaprop, malapropism,
   malfeasance, malpractice, malversation, marrowsky, misapplication,
   misappropriation, misconduct, misconstruction, misemployment,
   misfeasance, mishandling, mismanagement, mispronunciation,
   missaying, misuse, peculation, perversion, pilfering, pollution,
   poor stewardship, profanation, prostitution, solecism, spoonerism,
   ungrammaticism, violation