A make-weight is someone or something you add so the number or the amount comes out right — not because they are the important part. The picture under the word is an old shop scale: if the goods were a little light, you threw on a small extra piece, a make-weight, to make the weight. From there it grew to people. If a team needs eleven names and you are the eleventh, you may feel like a make-weight: you are there to fill the list. The word is a little cool, a little unkind, and more British than American. It is not praise. Though actually, people sometimes use it lightly, about themselves, to say they know they were not the star of the group.