Learner's definition of MERE
always used before a noun
1 — used to say that something or someone is small, unimportant, etc.
She was a mere child [=she was only a child] when her father died.
His voice did not rise above a mere whisper. = His voice did not rise above the merest [=slightest] whisper.
You can taste a mere hint of spice. = You can taste the merest hint of spice.
The trip takes a mere two hours. [=the trip takes only two hours]
You can own this car for a mere 20 dollars a week.
These mysteries can't be solved by mere mortals like us.
2 — used to say that something small is important or has a big effect or influence
The mere thought of going makes me nervous.
The mere fact that he agreed to help us is a good sign.
The mere/merest mention of his name makes her angry.
He gets sick at the merest sight of blood.