Definition of post-synch in English:

post-synch

verb

[WITH OBJECT]
  • Add a sound recording to (film or video footage) at a later time.

    • ‘It was shot silently with dialogue spoken in Italian by non-professionals (the men played themselves) with the intention of post-synching English dialogue.’
    • ‘It was and remains cheaper to shoot without synch-sound in acoustically problematic locations (downtown streets and hotel rooms) and later post-synch all the dialogue.’
    • ‘Dateline fleshes out the political background with a concise post-synched commentary; this works well, and does not detract from some stunning documentary film-making.’

Pronunciation:

post-synch

/pōstˈsiNGk/