boffo

A-OK, A1, awesome, bang-up, banner, beautiful, blue-chip, blue-ribbon, bonny (also bonnie) [chiefly British], boss [slang], brag, brave, bully, bumper, capital, choice, classic, cool [slang], corking, crackerjack, cracking, dandy, divine, dope [slang], down [slang], dynamite, excellent, fab, fabulous, famous, fantabulous [slang], fantastic, fine, first-class, first-rate, first-string, five-star, four-star, frontline, gangbusters (also gangbuster), gilt-edged (or gilt-edge), gone [slang], grand, great, groovy, heavenly, high-class, hot, hype [slang], immense, jim-dandy, keen, lovely, marvelous (or marvellous), mean, neat, nifty, noble, number one (also No. 1), numero uno, out-of-sight [slang], par excellence, peachy, peachy keen, phat [slang], prime, primo [slang], prize, prizewinning, quality, radical [slang], righteous [slang], sensational, slick, splendid, stellar, sterling, superb, superior, superlative, supernal, swell, terrific, tip-top, top, top-notch, top-of-the-line, top-shelf, topflight, topping [chiefly British], unsurpassed, wizard [chiefly British], wonderful