Sentence:  [T]o please her he promised to lay aside the universal <WSD>drabs</WSD> for the wedding day and to case his extremities in modern black cloth continuations, with an express stipulation that the <WSD>drabs</WSD> should again be in active service on the subsequent morning. 
Meaning of the word marked with <WSD> tags:  "Often in the (plural) form" '''(drabs)''': apparel, especially trousers, made from this fabric.