What are some words end with the suffix nees?

You're likely thinking of the suffix -ness, which denotes a state, quality, or condition. Here are some words ending in -ness:

* Happiness

* Sadness

* Kindness

* Goodness

* Darkness

* Cleanliness

* Weakness

* Illness

* Rudeness

* Business

* Readiness

* Seriousness

* Consciousness

* Effectiveness

* Liveliness

Let me know if you'd like more examples!