Sentence:  The fatal difference 'twixt his weight and mine, A second battle should he do this day : Nay, though outmatched I be, let but my mistress Give me the word: instant I'll take him on Here — now — at <WSD>catchweight</WSD>. 
Meaning of the word marked with <WSD> tags:  A weight category other than the standard weight categories: either an agreed-upon weight range or an agreement to allow any weight.