Wedding ceremony -- groom plans it around mid-January (8)
I believe the answer is:
nuptials
'wedding ceremony' is the definition.
('nuptials' can be a synonym of 'wedding ceremony')
'groom plans it around mid-january' is the wordplay.
'groom' is an anagram indicator.
'around' means one lot of letters goes inside another.
'mid' means to look at the middle letters.
The middle of 'january' is 'u'.
'plans'+'it'='plansit'
'plansit' anagrammed gives 'nptials'.
'nptials' placed around 'u' is 'NUPTIALS'.
(Other definitions for nuptials that I've seen before include "Marriage ceremony" , "Wedding - suit plan (anag)" , "Wedding ceremony" , "I slant up for a wedding" , "A wedding or marriage" .)