副詞 flat-out:

1. in a blunt direct manner
   同義詞：bluffly, bluntly, brusquely, flat out, roundly
2. at top speed
   同義詞：flat out, like blue murder

flat-out

adj.Informal （形容詞）【非正式用語】
Thoroughgoing; out-and-out:
徹底的；完全的：
例句：
a flat-out promotional campaign; a flat-out deception.
完全的促銷運動；徹底的欺騙