What word means serious or determined?

There are many words that mean serious or determined, depending on the specific nuance you want to convey. Here are a few options:

General serious or determined:

* Earnest

* Solemn

* Resolute

* Purposeful

* Intense

* Focused

* Driven

Stronger, more forceful:

* Unwavering

* Steadfast

* Unyielding

* Tenacious

* Relentless

* Grim

More intellectual or thoughtful:

* Deliberate

* Methodical

* Rigorous

* Contemplative

With a sense of urgency:

* Urgent

* Imperative

* Critical

The best word will depend on the specific context and the tone you want to create.