Discreet Retreat

If an ability refers to an outlaw or whether a player controls an outlaw, it’s referring only to permanents with one or more of the creature types specified above. Notably, it’s not referring to any spell or card not on the battlefield. However, other abilities may refer to an “outlaw spell” or “outlaw card” in a zone other than the battlefield. Those abilities refer to spells and cards with one or more of the specified creature types.

Outlaw is not a creature type. If an effect asks you to choose a creature type, you can’t choose outlaw.

You may spend the two mana added by the ability granted by Discreet Retreat on the same spell or activated ability or two different spells and/or activated abilities.

“Outlaw sources” include any objects with at least one of the Assassin, Mercenary, Pirate, Rogue, or Warlock creature types. This means you could spend the mana to activate the ability of an outlaw creature you control or an outlaw card in your hand or graveyard, for example.