Selcouth \SEL-kooth\ , adjective;
1. Strange; uncommon
This word is considered obsolete, but it caught my eye because it is similar to uncouth, a word which I know nothing about (other than the definition, I guess).
Selcouth is first attested in 888 and is a combination of Old English seld-an + cuð ("seldom" + "known"). Cuð became couth, which is also obsolete except as a back-formation from uncouth. The original meaning of couth was "well-known, familiar," so uncouth was "unknown." This evolved into "awkward, clumsy; strange," which led to a 'new' couth which means "cultured, well-mannered."