Meaning of “mere” - Learner’s Dictionary

mere

adjective [ always before noun ] uk us /mɪər/

B2 used to emphasize that something is not large or important:

It costs a mere twenty dollars.
The mere thought of (= Just thinking about) eating octopus makes me feel sick.
the merest

used to emphasize that something is small, often when it has an important effect:

She's upset by the merest hint of criticism.

(Definition of “mere” from the Cambridge Learner’s Dictionary © Cambridge University Press)