i Register
In some senses, frumpy is marked as dated. Watch for register when choosing this word.
adj
Dowdy, unkempt, or unfashionable.
She came to the door in a frumpy housedress and bedroom slippers.
Although still young at heart and head, he looks more and more like his old friend Archimedes, increasingly bearded and increasingly grey, with an otherworldly mien – a look that should earn him a spot in the online quiz featuring portraits of frumpy old men under the rubric “Prof or Hobo?”
Bad-tempered.