a nonstandard or ungrammatical usage, as unflammable and they was.
2.
a breach of good manners or etiquette.
3.
any error, impropriety, or inconsistency.
Origin: 1570–80; < L soloecismus < Gk soloikismós, equiv. to sóloik(os) (Sólo(i) a city in Cilicia where a corrupt form of Attic Greek was spoken + -ikos-ic) + -ismos-ism
[Latin soloecismus, from Greek soloikismos, from soloikizein, to speak incorrectly, from soloikos, speaking incorrectly, after Soloi (Soli), an Athenian colony in Cilicia where a dialect regarded as substandard was spoken.] sol'e·cist n., sol'e·cis'tic adj.