Possible Clues:

• Position not conducive to firing CO?
• (Do something) prematurely; not fully prepared
• In a position only partially prepared
• On the pitch, stroke young animal with head down, having broken leg joint
• One of 1 across, foul-sounding and may go off at it
• Go off at . . . .- . . . . like premature shot from gun (4-4)
• Go off at . . . . . . . . before being properly ready, like semi-rooster
• Go off at . . . . . . . ., being unready like semi-rooster
• Go off at . . . . . . . ., before you are ready
• Not a good thing to go off at