Cheerful relative between start and end of journey (6)
I believe the answer is:
jaunty
'cheerful' is the definition.
('jaunty' can be similar in meaning to 'cheerful')
'relative between start and end of journey' is the wordplay.
'relative' becomes 'aunt' (aunt is a kind of relative).
'between' is an insertion indicator.
'start and end of' says to hollow out the word (remove centre letters) (only the first and last letter remain).
'journey' with its centre taken out is 'jy'.
'aunt' inserted within 'jy' is 'JAUNTY'.
(Other definitions for jaunty that I've seen before include "Happy" , "Cheerfully self-confident" , "Sprightly and cheerful" , "Stylish" , "Cheerful and self-confident, perhaps with a swagger" .)