Nozzle-extrudable describes a material that can be pushed through a nozzle and deposited in a controlled stream. In manufacturing and 3D printing, that is only the first requirement: the material also has to flow at the right viscosity, keep its shape, and harden or cure predictably after extrusion.
This matters in cyber security because additive manufacturing is used for enclosures, fixtures, test parts, and sometimes deceptive or malicious physical objects. If a material is not truly nozzle-extrudable in practice, prints can sag, clog, or fail, which can break prototyping workflows or undermine the reliability of parts used in secure hardware and lab setups. Defenders care about the term when validating printer profiles, material handling, and process controls; attackers care because physically produced objects must still survive the manufacturing process to be useful.