General suffixes:
* -ation: This is a common suffix for forming nouns from verbs. It can create a noun meaning "the act of observing". For example, "observation".
* -er: This suffix creates a noun meaning "one who observes", like "observer".
More specific suffixes:
* -able: This suffix forms adjectives meaning "able to be observed", like "observable".
* -ance: This suffix can be used to form nouns that describe a state or quality, like "observance" (which is less directly related to "observe" but might fit in some contexts).
Alternative words:
You might also consider using other related words that don't require a suffix, such as:
* Observation
* Monitoring
* Surveillance
* Inspection
The best option will depend on the specific context and what you want to convey.