Synonyms of the word 
OBSERVING → OBSERVANT - PERCEPTIVE
observing
- v. present participle of observe.
- n. observation.
observant
- adj. Alert and paying close attention; watchful.
- adj. Diligently attentive in observing a law, custom, duty or principle; regardful; mindful.
perceptive
- adj. having or showing keenness of perception, insight, understanding, or intuition.
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