Literal translation
it's a soft file
Meaning
he's sly beneath a soft, gentle manner
Explanation
This expression describes a sly person whose gentle appearance hides a hypocritical or dangerous nature. Limo names the file, that tool which wears down metal through slow, quiet friction, though it can also mean lemon or silt (mud deposit) in other uses ; it is the tool's meaning that dominates here. Douço (soft, gentle) qualifies this file with an adjective one would rather expect for a pleasant person, creating the paradox that gives the image its bite : a file, by nature, wears down and cuts into things, whatever the apparent softness of its grain. The image echoes a well-known French counterpart, lime sourde, describing someone who works on those around them behind the scenes, through a series of small, patient inroads. Its register is one of social warning, used to hint that a pleasant-seeming person actually acts with calculation or ill will, quietly eroding whatever they touch before the victim even notices.