Mildly insane or eccentric; often, senile.
(ux)
{{quote-text|en|year=1897|author=Richard Marsh|title=The Beetle
(quote-book)|publisher=Angus and Robertson|location=Sydney|page=152|passage="Good God! I don't want another accident here. I should go dotty if I had to face all that again."
(quote-book)
Having an unsteady gait.
Having many dots.
A shotgun.
(quote-song)