filch

verb [col- loq]
furtar / afanar / rampinyar

We currently have the following entry for 'to pinch':

verb
robar
pessigar

We should almost certainly give the same Catalan equivalents as we have for 'filch' rather than the current 'robar'.

The GDLC defines 'furt' as an:
"acció delictiva consistent a apoderar-se, amb ànim de lucre, d'un bé moble d'altri contra la voluntat del propietari, sense violència o intimidació en les persones ni fent força en les coses furtades"

They define 'robatori' as a:
"variant del delicte de furt que alguns drets penals tipifiquen per l'apoderament violent de la cosa robada".

I don't believe anybody could ever be said to 'pinch' or 'filch' something violently or in an intimidating manner. They suggest, rather, theft of fairly small items of relatively little value without anybody seeing.