Decaying matter Mike extracted from dip (5)
I believe the answer is:
humus
'decaying matter' is the definition.
'humus' can be an answer for 'matter' (humus is a kind of matter). I am not certain of the 'decaying' bit.
'mike extracted from dip' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'extracted from' is a deletion indicator.
'dip' becomes 'hummus' (I've seen this before).
'hummus' with 'm' taken away is 'HUMUS'.
Can you help me to learn more?
(Other definitions for humus that I've seen before include "Compost" , "decomposing organic matter" , "Fertilising agent" , "Partially decomposed matter in the soil" , "Organic matter in topsoil" .)