It depends. Male Meowstic has the Hidden Ability Prankster, which gives +1 priority to status moves, and its movepool is focused on status moves.
Female Meowstic on the other hand, has the HA Competitive, which raises Special Attack when targeted by a stat-lowering move, and its movepool is more offense-orientated.
So if you want a support-ish Pokémon, go for male. If you want a Special Attacker, go for female.
Overall though, I believe male Meowstic is the better choice. It has better utility, with useful priority status moves such as Thunder Wave, Trick and Screens.
Female Meowstic, although having a larger offensive movepool, does not have higher Special Attack than male, and base 83 is not that amazing, although boosts me by Calm Mind or Competitive.
