sober; sedate; reserved; emotionally self-controlled
I had always known him to be such a staid character that I was really shocked one day when I heard him laugh.
Remember as ' Rahul Dravid stayed (staid) on the pitch for long time' relate Dravid maintaining dignity of the country. Staid--sounds like "STAYED"--Imagine you have always maintained your dignity and propriety in the place where you have stayed for so many years! Stay with dignity=staid