UNIDIOMATICALLY
Etymology
Adverb
unidiomatically (comparative more unidiomatically, superlative most unidiomatically)
In an unidiomatic way.
[…] a curious little extract from an Athenian letter which appeared in the 'Globe' of Friday last, apparently either written in English by a Greek, or translated into English unidiomatically, and with manifest traces of a foreign original.
Source: Wiktionary
UNIDIOMATIC
An*id`io*mat"ic*al, a. Etym: [Gr. idiomatical.]
Definition: Not idiomatic. [R.] Landor.
Source: Webster’s Unabridged Dictionary 1913 Edition