Yes, mature is a Scrabble word!

Adjective

1. Characteristic of maturity

2. Fully considered and perfected

3. Having reached full natural growth or development

4. Fully developed or matured and ready to be eaten or used

5. (of birds) having developed feathers or plumage; often used in combination

Verb

1. Develop and reach maturity; undergo maturation

2. Develop and work out fully in one's mind

3. Become due for repayment

4. Cause to ripen or develop fully

5. Grow old or older

6. Cause to ripen and discharge pus