What's the difference between grim and grum?

Grim

Definition:

(Compar.) Of forbidding or fear-inspiring aspect; fierce; stern; surly; cruel; frightful; horrible.

Example Sentences:

(1) This is the grim Fury on a rainy winter morning in Cannes.
(2) The level of prescribing of opioid painkillers – Percocet in Geni’s case – has soared, and with it the incidence of addiction, and addiction’s grim best friend: fatal overdoses.
(3) Patients with anti-NC1 antibodies were characterised by linear immune deposits along the glomerular basement membrane and the clinical outcome was invariably grim.
(4) The Mail branded the deal "a grim day for all who value freedom" and, like the Times, accused David Cameron of crossing the Rubicon and threatening press freedom for the first time since newspapers were licensed in the 17th century.
(5) ARD TV showing grim-faced FDP cadres: could this be the first time they fall out of national parliament in 60 years?
(6) It has said a better productivity performance and rising North Sea oil revenues will make the budgetary position less grim.
(7) Shields accepted that the Irish appeared more inclined to send up their grim fiscal situation than go out and riot.
(8) Inside the Islamic State ‘capital’: no end in sight to its grim rule Read more The Kurdish People’s Protection Units (YPG) militia and an alliance of rebels known as the “Euphrates Volcano” – backed US-led coalition air strikes – have seized swaths of territory from Isis, including the strategic border town of Tal Abyad .
(9) Yet, if that flurry of form pepped optimism, the injuries and displays in recent friendlies have provided a grim reality check.
(10) The dark, luxury air in the silent bedrooms of empty riverside apartments, their identical curving blocks clustered in threes and fours, grim and silent as gill slits, will be theirs.
(11) Chinese media and bloggers published images of three young children in blue school uniforms lying dead on the pavement – a grim echo of the high casualty rate at poorly constructed schools in Sichuan in 2008, when a bigger quake killed 87,000 people.
(12) The BCC survey represents a turnround from the end of last year, when it was predicting stagflation – a grim combination of zero growth and inflation.
(13) The human rights organisation, which has produced a series of in-depth reports detailing the grim working conditions of many of the 1.5 million migrant labourers engaged in a huge construction boom, said “little has changed in law, policy and practice” since the government promised limited reforms 12 months ago.
(14) Carcinoma of unknown histogenesis or primary site is an increasingly recognized syndrome regarded by most physicians as having a grim prognosis.
(15) "There are times when a swingeing sentence can act as a deterrent", as the judge at the trial was grimly to pronounce.
(16) The footage beamed back from the liberated districts of Ramadi is grim: a ghost town littered with debris and smashed concrete, destroyed storefronts, plumes of smoke, the sound of gunfire piercing the air as Iraqi soldiers speak on camera.
(17) It was my shortcomings as coach that caused this result,” said a grim-faced South Korea manager, Hong Myung-bo, who spent most of the post-match press-conference scratching his nose in apparent distress and deflecting comments about whether he would stay on as manager until next year’s Asian Cup.
(18) After grim news on the recession, at least one thing should become clearer: going back to where we were is no longer an option.
(19) While deplorable and to a degree self-defeating, this insouciant defiance also makes a grim kind of sense, both historically and reinforced by recent events.
(20) The entity carries a grim visual prognosis, as all ten eyes initially had no perception of light; improvement to light perception occurred in one instance.