How does the adjective ample differ from other similar words?

Some common synonyms of ample are abundant, copious, and plentiful. While all these words mean "more than sufficient without being excessive," ample implies a generous sufficiency to satisfy a particular requirement.

How do abundant and plentiful relate to one another, in the sense of ample?

Abundant suggests an even greater or richer supply than does plentiful.

When would copious be a good substitute for ample?

The meanings of copious and ample largely overlap; however, copious stresses largeness of supply rather than fullness or richness.

When is it sensible to use plentiful instead of ample?

In some situations, the words plentiful and ample are roughly equivalent. However, plentiful implies a great or rich supply.