Young’s Modulus is a mechanical property that measures the stiffness of a solid material. It measures the ratio between mechanical stress \sigma and the relative resulting strain \epsilon. And so, very simply:
\begin{equation} E = \frac{\sigma }{\epsilon } \end{equation}
Thinking about this, silly puddy deforms very easily given a little stress, so it would have low Young’s Modulus (\sigma \ll \epsilon); and visa versa. https://aapt.scitation.org/doi/10.1119/1.17116?cookieSet=1