clas

As an adjective rank

is heavy, serious, grievous.

As a noun clas is

clause (linguistics).

As an adjective confidential

is (meant to be) kept secret within a certain circle of persons; not intended to be known publicly.

As a noun clas is

clause (linguistics).

As an adjective classical

is of or relating to the first class or rank, especially in literature or art.

As a noun clas is

clause (linguistics).

As nouns the difference between monastery and clas

is that monastery is place of residence for members of a religious community (especially monks) while clas is a Celtic monastery.

As a proper noun celtic

is a branch of the indo-european languages that was spread widely over western and central europe in the pre-christian era.

As an adjective celtic

is of the celts; of the style of the celts.

As a noun clas is

clause (linguistics).