1. not able to be seen or noticed
2. not able to be measured or detected by scientific instruments or methods
Usage: scientific

Examples

• The changes in the patient’s condition were unobservable to the naked eye.
• Many subatomic particles remain unobservable with current technology.
• The effects of the new policy were unobservable in the short term.
• Dark matter is largely unobservable except through its gravitational effects.
• The microscopic organisms were unobservable without proper equipment.
• His emotional state remained unobservable to his colleagues.