The adjective "smashing" has been in use for a century.
OED:
2. colloq. Very good; greatly pleasing; excellent; sensational.
a1911 D. G. Phillips Susan Lenox (1917) II. vi. 164 When you get
dressed up a bit..you'll do a smashing business.
1914 W. Owen Let. 27 Dec. (1967) 310, I come in hungry to find a
‘smashin’ dinner.
1922 E. Wallace Flying Fifty-five xxxix. 236 I'd take a crack at
some of them with Fifty and even with Meyrick, who is a smashing
good horse.
1944 M. Paneth Branch Street 8 When the children came..to play
in the house they thought it ‘smashing’.
1948 Mind 57 418 The fact is, the verification principle is a
metaphysical proposition—a ‘smashing’ one if I may be permitted
the expression.
1959 Times Lit. Suppl. 2 Oct. 564/2 It is not her fault that the
publishers, in big letters on the jacket, promise ‘as smashing a
last sentence as we can recall!’ That promise is not fulfilled.
The final twist is surprisingly unsurprising.
1977 Chem. in Brit. 13 118/2 This is a smashing book for anyone
interested in surface chemistry and physics to have available on
his bookshelf.
Also there is the noun "smash" in the sense:
6. A great success; a film, person, play, song, etc., which enjoys
popular success; a hit (hit n. 4). Also attrib., esp. in smash hit
n.
1923 Variety 11 Oct. 16 (heading) ‘Rosie O'Reilly’ and ‘The
Fool’, Loop's Two Smash Hits.
1930 Times Lit. Suppl. 16 Oct. 841/1 An entirely strange girl;
whom anyone would have admitted to be a ‘smash’.
1931 Daily Express 21 Sept. 9/3 The magnates who had contracted
to buy the picture indulged in fits of doubt concerning its
prospects as a box-office ‘smash’.
1935 Amer. Speech 10 193/2 Terminology from other fields aids
the fashion editor... The sports writer is also responsible for
the smash hit dinner dress.
1935 P. G. Wodehouse Blandings Castle xii. 305 Our whole
programme is built around it. We are relying on it to be our big
smash.
1948 W. S. Maugham Colonel's Lady in Quartet 201 The English
publisher said to him: ‘We've not had a success like this with a
book of verse for twenty years.’.. The American publisher said to
him: ‘It's swell. It'll be a smash hit in America.’
1949 R. Chandler Let. 23 Apr. in Sel. Lett. (1981) 174 You can't
make me into a smash best seller.
....
--
Peter Duncanson, UK
(in alt.usage.english)