bungle
One bungling gang of robbers managed to attack the wrong building last week.
The bungling surgeon was asked to retire, rather than arrested and brought to trial.
Somehow the bungling referee managed to miss the most obvious penalty of this World Cup.

SMART Vocabulary: related words and phrases

Inability and awkwardness
accident-prone
adorkable
all thumbsidiom
amateurish
amateurishly
fumblingly
functional illiteracy
gauche
gauchely
gawkily
inexpertly
jack-of-all-trades
jack-of-all-trades, master of noneidiom
klutzy
like a bull in a china shopidiom
uncoordinated
uneducable
unenterprising
unequal
ungainly