KanjiJLPT N1
Mediocre

commonplace, ordinary, mediocre

Mnemonic

A workbench should be covered in sawdust and sweat from hard labor, but this one has only a single drop of effort on it — one lonely bead of sweat from a lazy carpenter. That's mediocre craftsmanship: one drop of work on an empty workbench produces nothing remarkable.
Additional thoughts
Picture a pristine, barely-used workbench with a single pathetic drop of sweat glistening on it. The contrast between a full workshop and this sad scene screams mediocrity. The emptiness of the workbench mirrors the emptiness of average, uninspired effort.
Quick recall
One drop of sweat on an empty workbench — that's mediocre effort.

Details

The keyword for 凡 is mediocre. This kanji conveys the sense of being ordinary, commonplace, or average—lacking any exceptional or distinguished quality. It refers to that which is mundane and unremarkable, standing in contrast to the extraordinary or outstanding. It can also carry the broader meaning of "all" or "in general," suggesting the totality of common, everyday things.
On'yomi
ぼん、はん
Kun'yomi
およ.そ、おうよ.そ、すべ.て

Used in vocab