Ah I love this word! So outlandish is an adjective very similar to 'weird' and 'strange', but it is closer to 'eccentric' in meaning.
For example, if someone's behaviour is outlandish, they act almost theatrically, like a character on TV or stage. Very over the top and extreme.
If someone is wearing outlandish clothing, it may be a bright orange jumper, a crazy hat and black trousers with bright green spots on!