This dictionary term meaning "old" is applied to words like "wast"
... Old words and phrases in English verb declensions:  
couldst... [DOC] [TLE] Archaic words | Oxford Dictionaries [PAR] These words are no longer in everyday use or have lost a particular meaning in 
current usage but are sometimes used to impart an old-fashioned flavor to 
historical novels, ... their current meaning, while others reveal the origin of a 
different modern word, .... like enough, probably .... wast, second person singular 
past of be.