This would make a major 7th chord. For a regular 7th chord, we need root, 3rd, 5th and b7 – but to say 'a flat 7' would be too easy to confuse with the chord A b7, a completely different thing.

The “weird,” or unsafe, chords often heighten the sense of tension and release that makes music work. The major seventh guitar intro in Old Dominion’s new single, “Never Be Sorry ...