What is the difference between sufficient and suffice?

Answer 1

Suffice is a verb, sufficient is an adjective.

So:

1) You can say "My dessert was sufficient", just as you can say "My dessert was green" or "My dessert was sweet". These are all adjectives.

2) Alternatively, you could say "My dessert will suffice", just as you can say "My dessert will sell" or "My dessert will explode". These are all verbs.

The interesting thing is that you can, as an alternative to example 2, say "My dessert will be sufficient", thereby using the adjective to achieve the same meaning.

However, by contrast there is not a corresponding alternative to example 1: You can not say "My dessert was suffice", yet you CAN say "My dessert was sold" due to the word "sold" being capable of acting both like an verb and an adjective depending on the context (Unlike "Sell", "Suffice" does not have a related word that can serve as both a verb and an adjective (that I can think of!)).