Dog soldier joining company, right (5)
I believe the answer is:
corgi
'dog' is the definition.
(corgi is a kind of dog)
'soldier joining company right' is the wordplay.
'soldier' becomes 'gi' (government issue or general issue).
'joining' says to put letters next to each other.
'company' becomes 'co' (abbreviation).
'right' becomes 'r' (common abbreviation).
'co'+'r'='cor'
'gi' after 'cor' is 'CORGI'.
(Other definitions for corgi that I've seen before include "One of the Queen's dogs?" , "Cardigan, possibly" , "The Queen's favourite?" , "Queen likes this" , "man's best friend" .)