Noun
In the army, a soldier who feigns himself sick, or who induces or protracts an illness, in order to avoid doing his duty; hence, in general, one who shirks his duty by pretending illness or inability.
Source: Webster's dictionaryBy definition, the malingerer is knowingly deceitful (although malingering itself has also been called a mental illness or disorder). Source: Internet
Service members, themselves, complicated matters by unofficially leaving hospitals, hastily returning to their units to rejoin battle so as to not appear a malingerer. Source: Internet