Catch-as-Catch can" or Scientific wrestling is defined as, "Using or making due with what ever means are available".
Catch wrestling, a classical hybrid grappling style, was developed in Britain circa, early 18th Century then later refined and popularized by the wrestlers of traveling funfairs who developed their own submission holds, or "hooks", into their wrestling to increase their effectiveness against their opponents.
Catch wrestling derives from a number of different styles, the English styles of Cumberland and Westmorland wrestling, Cornwall and Devon wrestling, Lancashire wrestling, Irish collar-and-elbow wrestling, Greco-Roman wrestling, Japanese Judo & Ju-Jutsu and styles of the Iranian and Indian subcontinent such as Pehlwani and Varzesh-e Pahlavani.
The father of Olympic free-style and collegiate Folk-style wrestling, It's dominance in matches against other wrestling styles gained worldwide notoriety around the mid 1800's. During this time it found its way to North America via immigrants and world travel.
When Catch Wrestling reached the United States in the late 19th and early 20th century it became extremely popular with the wrestlers of the traveling carnivals.
The carnival's wrestlers challenged the locals as part of the carnival's "athletic show" and the locals had their chance to win a cash reward if they could defeat the carnival's strongman by a pin or a submission.
Eventually, the carnival's wrestlers began preparing for the worst kind of unarmed assault and aiming to end the wrestling match with any tough local quickly and decisively via submission.
A hook was a technical submission which could end a match within seconds. As carnival wrestlers traveled, they met with a variety of people, learning and using techniques from various other folk wrestling disciplines, many of which were accessible due to a huge influx of immigrants in the United States during this era.
The term "catch as catch can" is generally understood to mean "catch (a hold) anywhere you can".
Catch wrestlers can win a match by either submission or pin, and most matches are contested as the best two of three falls.
Also just as today "tapping out" signifies a concession as does shouting out "Uncle!", back in the heyday of catch wrestling rolling to one's back could also signify defeat.
The term, "No holds Barred" originated with Catch wrestling-as there are NO ILLEGAL SUBMISSION HOLDS, PINS OR TAKE DOWNS!
Which makes it an extremely effective combat sport and ideal for reality based self defense and mixed martial arts.