A ridiculous, silly or stupid person.
'dingbat' originally refers
to to a character or symbol used
in typesetting which gives an instruction
to the printer. These should be removed before
is published, but were occasionally left in by mistake. The character made no sense to non-typesetters and the association of "dingbat" with "nonsense" and "forgetfulness" carried over to describe people.
a dingbat, I asked her to buy me yogurt and she got me cream.
This end of year
report is riddled with inaccuracies. Looks like we've got a dingbat in the mix.
(sarchastic) Nice one Paul, a spectacular display of ding-battery.