Sentence:  Almost every writer of power will occasionally use with strong effect an <WSD>archaic</WSD> term that he has unearthed from the treasures of the older English vocabulary. This is especially true of poets, who recognize that the unusualness of the <WSD>archaic</WSD> word will sometimes heighten the poetic effect. 
Meaning of the word marked with <WSD> tags:  No longer in ordinary use, though still used occasionally to give a sense of antiquity.