A “loop” can mean many things. First, as a noun. There could be a loop (curva) in a road, in a river (meandro) or in a rope (lazada). Sometimes pilots “loop the loop”, (rizar el rizo).
Now as a verb, “to loop”. Sometimes, mortals loop a rope around a post (los mortales pasan una cuerda alrededor de un poste). Another example: Leila looped the dog´s lead over the post (…enganchó la correa del perro en el poste).
A “loophole” is a gap in the law (una laguna jurídica o legal), perhaps unintended by the lawmakers. A loophole helps to avoid the application of a law. Some clever lawyers say that every law has a loophole (hecha la ley).
There is an adjective: loopy. An idea can be loopy (estúpida), and a person too (chiflada).
There are some people who are “in the loop” (están en el grupo informado), and there are others who are “out of the loop”, that is, they are not being informed about something important (están fuera del grupo de gente informada). So, pilots who “loop the loop” might be loopy. The same pilot might look for loopholes in the law to avoid some rules or taxes, and loop their dog´s lead around a post. They might be “out of the loop” when it comes to decisions about the airline´s future.