MixedCase words/phrases are words/phrases which have multiple capital somewhere within them. ThisIsAnAcceptableMixedCasePhrase. thisIsAnAcceptableMixedCasePhrase however THISISNot norISTHIS or is Log4J. However you can make WikiWords from non MixedCase words by putting them in double square brackets ('') like [[Thisnonwikiword.
However please don't test this here. Test it in the SandBox.
TESTING