Mis-tǽcan

According to the Old English Dictionary:

mis-tǽcan

to teach wrongly :-- Gif ða láreówas wel tǽcaþ, ðonne beóþ hí gehealdene; gif hí mistǽcaþ, hí forpǽraþ hí sylfe, Homl. Th. ii. 50, 4. [Gen. and Ex. mis-tagte mis-directed.] mis-tæcan