Acted silently to curtail dimmer switch (5)
I believe the answer is:
mimed
'acted silently' is the definition.
'mimed' can be an answer for 'acted' (miming is a kind of acting). I'm not certain of the 'silently' bit.
'curtail dimmer switch' is the wordplay.
'curtail' means to remove the last letter (I've seen 'curtailed' mean this).
'switch' indicates anagramming the letters.
'dimmer' with its final letter taken away is 'dimme'.
'dimme' anagrammed gives 'MIMED'.
'to' is the link.
Can you help me to learn more?
(Other definitions for mimed that I've seen before include "Took off <" , "made a charade" .)