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deep (colour); dark
strong (flavour, smell, etc.)
thick (consistency); dense
strong (possibility, etc.)
thick (i.e. "as thick as thieves"); close; deep (love, etc.)
彼女は濃い化粧をしていて目立つ。
She wears heavy makeup.
このコーヒーは味が濃くて目が覚める。
This coffee has a strong flavor.
今朝入れたコーヒーはいつもより濃かった。
The coffee I brewed this morning was darker than usual.