generosity's evil twin, hoarding pennies while time spends itself for free
means Unwilling to give or spend, mean with money or resources to a grudging fault.
from Likely from "sting" plus the adjective ending "-y," carrying the idea of something sharp and biting — a stingy person pinches like a nettle. There's an older, separate "stingy" meaning "having stings," and the two senses tangle, but the miserly meaning that survives suggests someone whose tight-fisted ways leave a little hurt behind.
ebenezer scrooge — dickens character who famously refused to give bob cratchit coal and hated christmas charity
howard hughes — billionaire who obsessively hoarded money while living in squalor, refusing to spend on basic maintenance
hetty green — 19th century american businesswoman worth $2 billion (inflation-adjusted) who wore the same dress for years and refused medical care for her son to save money