Definition of "meaningful"

"This baby is the one that counts. I dare say Polly here wouldn't want any other, would you, Polly?""This baby, this baby," said Polly.Wolcott gave Peter Horn a meaningful look. Horn interpreted it correctly. This baby or no more Polly ever again. This baby or Polly would be in a quiet room somewhere staring into space for the rest of her life.

1948, Ray Bradbury, Tomorrow's Child

But the Danes remained resolute in defence - largely thanks to a spirited display by captain Daniel Agger - and they went ahead with their first meaningful attack.

2012 June 9, Owen Phillips, “Euro 2012: Netherlands 0-1 Denmark”, in BBC Sport‎

In setting out a broad-brush approach, the Arriva-owned operator doesn't make any specific requirements, but it says the replacement trains "must achieve a meaningful reduction in the exhaust emissions and exterior noise levels compared to Chiltern's existing DMUs".

2023 August 23, Mel Holley, “Network News: ... while Chiltern Railways targets low-emissions stock”, in RAil, number 990, page 7