A phrase, formed by four unclued lights, incorporates a definition of the other unclued lights and an indication of the way in which they are entered. Two unclued lights are hyphened.
 

Across

 
7    Nun, see, has to thank saint (6)
12    Rude man I’d sadly not held in high regard (9)
13    Festival taking shape in chaos (5)
15    New start for team in dark English strip (9)
16    Silence almost complete around pod (6)
20    Relative amateur after good chance missing nothing (7)
21    Cotton worn by eastern artist (6)
22    Left behind baron in middle bracket (6)
24    Idle...