Much like the use of obvi in English listed here. Obvio is a shortened form of obviamente, used especially in Argentine Spanish.
- ¿Trajiste las valijas?
- ¡Obvio! ¿Qué te parece? No soy boludo.
The opposite of nocturnal; by day.
Most people are diurnal, although some people are like night-owls and are nocturnal.