archaic
The definition for archaic is "Characteristic of an earlier time." Used in a sentence: In the world of high fashion, two–year–old shoes are considered positively archaic.
clarity
The definition for clarity is "Clearness." Used in a sentence: The refreshing water in the mountain stream was remarkable for its clarity.
interminable
The definition for interminable is "Never ending, or seemingly endless." Used in a sentence: The impatient Zoe found the longwinded lecture interminable.
intricate
The definition for intricate is "Having complex and interrelated parts." Used in a sentence: The intricate poem baffled most readers with its numerous obscure metaphors.
periodic
The definition for periodic is "Occurring at regular intervals." Used in a sentence: The periodic innterruptions of the cuckoo clock prevented Li from concentrating.