There's something equable about a Dutch one (5)
I believe the answer is:
treat
'there's something equable' is the definition.
I can't tell whether this definition defines the answer.
'about a dutch one' is the wordplay.
'about' means one lot of letters goes inside another.
'dutch one' becomes 'tret' (I can't explain this - if you can you should give a lot more credence to this answer).
'a' going inside 'tret' is 'TREAT'.
Can you help me to learn more?
(Other definitions for treat that I've seen before include "Practise medicine" , "Deal with - source of great pleasure" , "Stand a drink" , "Behave towards" , "Entertain at one's own expense" .)