Etymology From older French amunition, rebracketing of la munition (“the war supplies”) as l'amunition. Ultimately from Latin; see munition for more.
1
Articles used in charging firearms and ordnance of all kinds; as powder, balls, shot, shells, percussion caps, rockets, etc.
Hiro risks turning on a small flashlight, uses it to rummage around the yatcht, picking up valuable stuff: a few bottles of (presumably) drinkable water, some food, extra ammunition for his nine.1992, Neal Stephenson, Snow Crash, page 359:
2
Obsolete Military stores, or provisions of all kinds for attack or defense.
ammunition bread
ammunition shoes
3
Figuratively Arguments and information that can be used against the other party in a conflict.
They say that the booklet gives them ammunition which is proving effective in breaking down resistance against home building which was created by false propaganda.1938, American Lumberman, page 52:
As long as the integration fight is in progress, some Southerners are willing to believe anything if it gives them ammunition in their fight to "retain our traditional way of life." If you have any wise bits of philosophy, please pass them along.1960, America, Volume 104, America Press, page 697:
3 more examples
Providing your administrator(s) with evidence of research progress gives them ammunition to request additional funds from the site-based management pool.2005, Blanche Woolls, David V. Loertscher, The Whole School Library Handbook, American Library Association, →ISBN, page 146:
The first thing to do is NOT constantly defend and argue with the ex or the children. It gives them ammunition and fuels their engines to come after you. In addition, you are just giving them more to use against you.2010, Joan Kloth-Zanard, Where Did I Go Wrong? How Did I Miss the Signs? Dealing with Hostile Parenting & Parental Alienation, Lulu.com, →ISBN, page 109:
However, preventing a vote from taking place could give ammunition to the SNP, which argues that Scotland’s view carries little weight in the union.2017 February 27, Mure Dickie, Henry Mance, “Theresa May’s speech to head off Scottish independence poll”, in Financial Times: