Wandering casually initially, I had a day going uphill (7)
I believe the answer is:
nomadic
'wandering' is the definition.
(I know that wandering can be written as nomadic)
'casually initially i had a day going uphill' is the wordplay.
'initially' indicates taking the first letters.
'i had' becomes 'i'd' (contraction).
'day going' becomes 'mon' (I can't justify this - if you can you should give a lot more credence to this answer).
'uphill' is a reversal indicator (in a down clue, letters go up).
The initial letter of 'casually' is 'c'.
'c'+'id'+'a'+'mon'='cidamon'
'cidamon' in reverse letter order is 'NOMADIC'.
Can you help me to learn more?
(Other definitions for nomadic that I've seen before include "Lacking fixed home" , "Perhaps unsettling" , "always moving?" , "constantly moving" , "Peripatetic" .)