General:
* Anticipating
* Expecting
* Holding on
* Pondering
* Delaying
* Holding back
* Biding time
* Standing by
* Remaining
* Remaining stationary
More specific:
* Impatient: fidgeting, fretting, yearning, longing, pining
* Patient: enduring, bearing, persevering, sustaining
* Passive: standing idly, inactive, dormant, quiescent
* Active: observing, watching, listening, monitoring
The best synonym for you will depend on the specific situation and the nuance you want to convey.