Heard rule had bad conditions (4)
I believe the answer is:
rain
'heard rule had bad conditions' is the definition.
I can't judge whether this defines the answer.
'heard rule' is the wordplay.
'heard' indicates a 'sounds like' (homophone) clue.
'rule' becomes 'reign' (synonyms).
'reign' is a homophone of 'RAIN'.
Can you help me to learn more?
(Other definitions for rain that I've seen before include "Wet weather" , "Fall wetly" , "The right" , "The ---, it ---eth every day (T.Night)" , "Precipitation" .)