Henry takes flight, which is not very bright (4-5)
I believe the answer is:
half-light
'henry takes flight which is not very bright' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'henry takes flight' is the wordplay.
'henry' becomes 'hal' (short for Henry).
'takes' says to put letters next to each other.
'hal'+'flight'='HALF-LIGHT'
Can you help me to learn more?
(Another definition for half-light that I've seen is " Poor visibility".)