«Otherwise» is an adverb and conjunction. It can mean “si no”, “de otra manera”, “de lo contrario” and “aparte de eso”.
Let´s examine some examples.
- We should leave now. Otherwise, we will be late (… si no, vamos a llegar tarde).
In the same context you could say… “if not, we will be late”.
- I have to put on my hat. Otherwise, I am ready to go out (…aparte de eso, estoy listo para salir).
- Apart from one point Ricardo´s thesis is, otherwise, a great piece of work (aparte de eso…..es un trabajo excelente).
- Mr. Podemos would do it by any means, legal or otherwise (….lo haría por todos los medios, legales o no).
- How can it be otherwise? ¿Cómo no va a ser así?
Please observe the use of the comma. At the beginning of a sentence a comma should follow. Otherwise, …. In the middle of the sentence: a comma, otherwise.