arreglar, verb:

to do up; to sort out

Arreglar appeared in a recent Word of the Day in one of its key meanings, to fix:

¿Sabrás arreglarme la llave?
Could you fix the faucet for me?

When applied to houses, rooms and so forth, arreglar means to decorate, to do up:

Este verano hemos arreglado la cocina.
This summer we did up the kitchen.

When you use arreglar with the words la situación, el asunto, el problema, and la vida, it conveys the meaning to sort out:

Si tienes algún problema él te los arreglará en seguida.
If you have any problems he’ll sort them out for you straight away.

Va a ser muy complicado arreglar esta situación.
It’s going to be very complicated to sort out this situation.