Definition from Wiktionary, the free dictionary
- (sports) Peak form, optimal form, excellent form.
1960, P. G. Wodehouse, Jeeves in the Offing, chapter IX:
- I don't know if you happen to take Old Doctor Gordon's Bile Magnesia, which when the liver is disordered gives instant relief, acting like magic and imparting an inward glow? I don't myself, my personal liver being always more or less in mid-season form, but I've seen the advertisements.