If you have a good competitive moveset for Mothim, post an answer below and upvote the best ones. Movesets for any of its pre-evolutions can also be shared on this thread.
Be sure to include full set details in your post, e.g. items, abilities, natures and EVs. Some explanation, including the intended game mode for your set, is also appreciated. Access the full list of guidelines here.
Mothim Pokédex and learnset for reference.
Gen V
Mothim (M) @ Focus Sash
Trait: Tinted Lens
EVs: 252 SAtk / 4 SDef / 252 Spd
Modest Nature (+SAtk, -Atk)
Gen 7 (USUM)
Mothim @ Choice Scarf Ability: Tinted Lens EVs: 4 HP / 252 Atk / 252 Spe Adamant Nature - Lunge - Aerial Ace - Facade - U-Turn
This is probably gimmicky but oh well. Gen 7 ZU Mothim (M) @ Leftovers Ability: Swarm EVs: 252 HP / 4 Atk / 252 SpD Careful Nature - Lunge - Toxic / Defog - Roost - U-turn
Lunge is STAB that lowers the opponent's attack every time it hits. Toxic is to poison Pokémon switching in. Defog can be used instead to clear entry hazards on your side. Roost is for healing. U-Turn is for pivoting.
Mothim @ Choice Specs Ability: Tinted Lens Mild Nature EVs: 4 HP / 252 SpA / 252 Spe - Bug Buzz - Air Slash - Psychic - Energy Ball