buttoned-down

adj.

1.

conservatively formal and businesslike in dress and manner. a colorful character in the buttoned-down, dull-gray world of business. - Newsweek

Adj.

1.

buttoned-down - unimaginatively conventional; "a colorful character in the buttoned-down, dull-gray world of business"- Newsweek Synonyms: button-down, conservative

button-down, conservative, conventional