misaligner
misperceiver
misapplier
misplacer
mislabeler
misstater
mislayer
misconstruer
misdealer
misdescriber
misunderstander
misidentifier
misreader
misconceiver
misteacher
misguider
misbehaver
belittler
misdirector
misspeaker
misreporter
mismanager
misjudger
misrepresenter
misinformer
obscurant
misfirer
misappropriator
miseducator
would lose one's head if it wasn't attached
dishonourer
mispronouncer
mishandler
discommender
discreditor
misnamer
mishearer
undeceiver
noncomprehender
disinformant
confounder
underpredictor
misshaper
foister
disinformer
deludee
refounder
contorter
quasher
distortionist