1.Definition: completely lacking in playfulness

Related Adjective(s):serious, unplayful

2.Definition: dignified and somber in manner or character and committed to keeping promises

"As sober as a judge"

Related Adjective(s):grave, sedate, solemn

3.Definition: lacking brightness or color; dull

"Sober Puritan grey"

Related Adjective(s):drab, somber, sombre

4.Definition: not affected by a chemical substance (especially alcohol)