Spoiling refers to making something worthless or spoiled, often by carelessness or neglect.
When we talk about spoiling, we usually mean that something has been damaged or ruined. For example, if you leave a ripe apple out in the sun, it will spoil and become mushy. Or, if you don't use up all the leftovers before they go bad, they'll spoil and have to be thrown away. Sometimes, "spoiling" can also mean that someone is being overly generous or giving too many treats to children, so they become spoiled. In this case, we're talking about a child who gets everything they want without having to work for it, and might even start behaving badly because of it.
How common is "spoiling"?
Word spoiling is considered rare in modern English. It has a balanced usage among all categories: speech, fiction, newspapers and academic texts.
Definitions
verb
To strip (someone who has been killed or defeated) of their arms or armour.
To strip or deprive (someone) of their possessions; to rob, despoil.
To plunder, pillage (a city, country etc.).
To carry off (goods) by force; to steal.
To ruin; to damage (something) in some way making it unfit for use.
To ruin the character of, by overindulgence; to coddle or pamper to excess.
Of food, to become bad, sour or rancid; to decay.
Example: Make sure you put the milk back in the fridge, otherwise it will spoil.
To render (a ballot paper) invalid by deliberately defacing it.
To reveal the ending or major events of (a story etc.); to ruin (a surprise) by exposing it ahead of time.