Ample traditionally means more than enough, referring to things that are very large, wide, plentiful, or copious. But in modern usage, ample is often used to mean just enough or sufficient, without implying largeness or greatness.
The conflicting definitions can lead to confusion. For example, if I say, “I work two jobs to earn ample money to feed my children,” you might conclude either (1) that I like to earn extra money so I can keep my kids nice and plump, or (2) that I must work two jobs in order to sufficiently feed my children. Still, in most cases, we can rely on context to figure out what a writer means by ample.
These writers use ample in the old sense, to mean more than enough:
The year just past provided ample evidence of the unpredictable nature of that elusive quantity known as news. [New York Times]
Gingrich’s record of controversy, his ethical violations while speaker and colourful private life all provide ample ammunition. [Guardian]
Wilson was snapped carrying two chihuahuas, the pooches nestled alongside her ample chest. [New York Post]
And in these examples, ample means just enough or sufficient:
Debt isn’t necessarily toxic for companies, as long as the companies generate ample cash flow to service the debt payments. [USA Today]
Syria is struggling to afford and secure ample food supplies for its domestic population … [Wall Street Journal]
[They] complained that members of the public … had not been given ample opportunity to be heard. [Patch]