serious-minded

He saw his duty plainly; he was serious-minded; he had no sense of humour.

His attitude was comically that of a serious-minded European tourist.

A serious-minded maid served them with salad and thin bread-and-butter.

He was a very steady, serious-minded person, and yet full of life and fun.

It's the funniest strike that ever happened to a serious-minded sex.

And then he is a serious-minded man now, is Monsieur Georges.

They were grown up, too serious-minded to act such a comedy.

The serious-minded housemaid is not content to do what she is told to do.

Grant was the most serious-minded of the four and everything he did he did with all his heart.

And levity in those who ought to be serious-minded is levity to me wherever I find it.