Most disagreeable to make Thea travel around the south for hours (8)
I believe the answer is:
harshest
'most disagreeable' is the definition.
Both the answer and definition are superlative adjectives. Perhaps there's an association between them I don't understand?
'thea travel around the south for hours' is the wordplay.
'thea' becomes 'ars' (I can't explain this - if you can you should give a lot more credence to this answer).
'travel around' indicates an anagram (I've seen 'travelling around' mean this).
'south' becomes 'S' (abbreviation).
'for' says to put letters next to each other (I've seen this in other clues).
'hours' becomes 'h'.
'the'+'s'='thes'
'thes' anagrammed gives 'hest'.
'ars'+'hest'='arshest'
'arshest' put after 'h' is 'HARSHEST'.
'to make' is the link.
Can you help me to learn more?
(Another definition for harshest that I've seen is " Most severe".)