all hat and no cattle

Related to all hat and no cattle: Mugabe, Sir Francis Drake

all hat and no cattle

Full of talk that is more impressive than that which one actually possesses or is able to do. Primarily heard in US, South Africa. He talks as though he knows more than anyone else, but he's all hat and no cattle.
See also: all, and, cattle, hat, no
Farlex Dictionary of Idioms.

all hat and no cattle

AMERICAN, INFORMAL
If you describe someone as all hat and no cattle, you mean that they seem impressive or exciting but in reality they do not do much. On this issue, western leaders are all hat and no cattle. Note: This expression comes from the West of America, where cowboys (= people who look after cattle) wear large hats.
See also: all, and, cattle, hat, no
Collins COBUILD Idioms Dictionary, 3rd ed.
See also:
  • be all hat and no cattle
  • cattle
  • big hat, no cattle
  • all bark and no bite
  • cat's pajamas
  • pajama
  • pyjama
  • the cat's pajamas
  • the cat's whiskers/pyjamas
  • a stonker of a (something)