1. One who observes or takes notice; observer 
2. One who makes a remark

Derived forms: observators

• public speaker
• public speaking
• public square
• public toilet
• public transit
• public transport
• public treasury
• public trust
• public utility
• public utility company
• public violence
• public works
• public-relations campaign
• public-service corporation
• public-spirited
• publically
• publican
• publication
• publicise
• gusset plate
• gusseted
• gussy
• gussy up
• gust
• gustation