One of the unclued entries (two words) defines the others (two of which are hyphened), which are all real words. Collins, not Chambers, confirms 23D. Ignore one accent in the unclued entries and another elsewhere.

Across

1    Clergymen demolishing a church helping its loss of status (14)
9    See missing competitor getting ready for Gulf states? (4)
12    Vulgar display that may be flashing entertains women (4)
14    Hook, at sea, a noted murder victim (6)
16    Support one going to university with father’s backing (5)
17    Noble peers regularly dated artefacts (5)
20    Designer wanting introduction to peregrine falcon (7)
21    Perhaps miss the race somehow (7)
24    Avoid...