Regarding penetrating article by celebrity getting middling review (5-4)
I believe the answer is:
three-star
'middling review' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.
'regarding penetrating article by celebrity' is the wordplay.
'regarding' becomes 're' (re can mean regarding, concerning).
'penetrating' means one lot of letters goes inside another.
'article by' becomes 'the' (the definite article in English. I am not sure about the 'by' bit.).
'celebrity' becomes 'star' (a star is a celebrity or famous person).
're' put inside 'the' is 'three'.
'three'+'star'='THREE-STAR'
'getting' acts as a link.
Can you help me to learn more?
(Another definition for three-star that I've seen is " Mid-range".)