Archaickou
Archaickou is a Czech adjective form meaning archaic. It is the feminine singular instrumental or accusative form of the adjective archaický, which describes something old-fashioned, ancient, or from an earlier period. This form is used before feminine singular nouns in those cases, for example: archaickou formou (in an archaic form), archaickou literaturou (with archaic literature), or archaickou řečí (in an archaic way of speaking).
In broader use, archaický describes objects, styles, or usages from the past that are no longer current.
Etymologically, archaický derives from the Greek archaios (ancient), with influence through German archaisch and French archaïque
Overall, archaickou serves as a grammatically specific form used when describing feminine nouns in particular cases,