observant

The quirky tenor of his voice, combined with his observant, mocking tone, gelled perfectly with the screwball proceedings.

But his own observant eyes automatically reporting on the darkening landscape checked him.

His low 'snarling' note attracts the attention of only the observant.

Perhaps he was a little too much engrossed in his own perplexities to be as observant as usual.

The light-heartedness of the Celt is another feature which strikes the least observant stranger.

The intimate yarn of the observant soldier home on leave, who could trust his listener, is superior to much one sees in print.