Definition of "tightener"

One proposed going to Hungerford-market to do a feed on decayed shrimps or other offal laying about the market; another proposed going to Covent-garden to do a 'tightener' of rotten oranges, to which I was humorously invited; […]

184?, Henry Mayhew, London Labour and the London Poor

Now a belt like this is a great saving to a man inasmuch as he can save many a meal by wearing it; all you have to do if you want to save a meal is to buckle in a hole or two tighter, and you will feel as if you have had a tightener and will not miss your dinner for that day.

1876, William Green, Charles Hindley, The Life and Adventures of a Cheap Jack, page 55