Clue: At first, cinemagoer natters rudely during tear-jerker, causing dismay (13)
Answer: CONSTERNATION
Explanation: Definition: dismay
A charade of C ('at first, **C**inemagoer') plus ONSTERNATION, an envelope ('during') of STERNAT, an anagram ('rudely') of 'natters' in ONION ('tear-jerker').