poor mouth

noun, Informal.
1.
a person who continually complains about a lack of money.
2.
a plea or complaint of poverty, often as an excuse for not contributing to charities, paying bills, etc.
Idioms
3.
cry poor mouth, to complain, especially habitually, about a lack of money.
Also, talk a poor mouth.
Origin
1815-25

poor-mouth

[poo r-mouth] /ˈpʊərˌmaʊθ/
verb (used without object), poor-mouthed
[poo r-moutht, -mouth d] /ˈpʊərˌmaʊθt, -ˌmaʊðd/ (Show IPA),
poor-mouthing.
1.
to lament or argue that one is too poor; plead poverty.
verb (used with object), poor-mouthed
[poo r-moutht, -mouth d] /ˈpʊərˌmaʊθt, -ˌmaʊðd/ (Show IPA),
poor-mouthing.
2.
to declare (one's ability, power, position, etc.) to be inadequate or disappointing, sometimes as an intentional understatement; downplay:
We know you're just poor-mouthing your skill at playing bridge—you're a good player.
3.
Origin
1965-70; Americanism; orig. in verb phrases put up a poor mouth, make a poor mouth
British Dictionary definitions for poor-mouth

poor mouth

noun
1.
unjustified complaining, esp to excite sympathy: she always has the poor mouth
verb (transitive)
2.
(informal) to speak of disparagingly; decry
Slang definitions & phrases for poor-mouth

poor-mouth

verb
  1. To deny one's wealth and advantages; emphasize one's deficiencies; Talk Poor Mouth: Richard Nixon often poor-mouthed his chances (1965+)
  2. To deprecate severely; bad-mouth: I'm not going around poor-mouthing the war (1967+)

[make a poor mouth, ''to whine, make the worst of things,'' is found as Scots dialect by 1822]