Usually a charmer, but one of a dangerous nature. Attractiveness is subjective, as it usually is. Tends to be quite intelligent, however that does not disclose anything about their mental capacities nor their ability to judge social situations.
The name Allan is now more popular amongst the older generation, thus most Allans would be approaching mid-life, if not already beyond.
Person 1: "So, who was that person flirting with someone half their age?"
Person 2: "Oh, it must have been Allan."