No polynomial time approximation algorithm better than $n^{1 − ε}$
The sentence means that for every $\epsilon &gt; 0$ there is a polytime reduction $f_\epsilon$ that takes an instance $\phi$ of SAT into a pair $(G,k)$ such that:


If $\phi$ is not satisfiable then $G$ has no $k$-clique.
If $\phi$ is satisfiable then $G$ has an $n^{1-\epsilon} k$-clique.


An $n^{1-\epsilon}$-approximation algorithm for MAX-CLIQUE can be used to distinguish the two cases.

The running time of $f_\epsilon$ indeed depends on $\epsilon$, which probably appears in the exponent, that is, $f_\epsilon$ runs in time $n^{g(\epsilon)}$, where $g(\epsilon)$ tends to $\infty$ as $\epsilon \to 0$.