The word "stiff" means rigid or not easily bendable. It can also describe someone who lacks flexibility or is very formal and serious in their behavior. Full definition
But a year later it's facing stiffer competition with an updated and improved design. (androidcentral.com)
I then thought about its tendency to lean and pitch, but you don't need very stiff suspension with such a good chassis and low weight transfer. (evo.co.uk)
But he's also facing stiff competition in the form of four Best Picture nominees, so that's like all she wrote. (incontention.com)