Water that dishes and cooking utensils have been washed in. / (by extension) Anything dull and lacking interest or flavour.

plural of dishwater

(simile) Boring; ordinary; exceedingly dull.

plural of dishwater blond

Of a dark blond colour/color bordering on light brown.

A dark shade of blond, bordering on light brown. / A person with dark blond hair.

Resembling dishwater.