a.

1. 明确的，确切的
   She made no definite answer.

   她没有作明确的回答。

2. 一定的，肯定的
   It's definite that he'll be late again.

   他肯定又要迟到。

3. 限定的

adj.

1. clearly stated or decided; not vague or doubtful.
   ▸(of a person) certain or sure about something.
2. clearly true or real.
3. having exact and discernible physical limits.