Letter from pair of kids describing New Year (8)
I believe the answer is:
landlady
'letter' is the definition.
(someone who lets property)
'pair of kids describing new year' is the wordplay.
'pair of kids' becomes 'lad lad' (lad means a young boy).
'describing' means one lot of letters goes inside another (describe can mean to form the outline of).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'year' becomes 'y'.
'ladlad' enclosing 'n' is 'landlad'.
'landlad'+'y'='LANDLADY'
'from' acts as a link.
(Other definitions for landlady that I've seen before include "Mistress of an inn" , "Woman with tenants, or a pub" , "country-woman" , "Lodging keeper" , "She has tenants or customers" .)