An ancient royal pub joins a row over hotel (7)
I believe the answer is:
pharaoh
'an ancient royal' is the definition.
'pub joins a row over hotel' is the wordplay.
'pub' becomes 'ph' (public house).
'joins a row' becomes 'ara' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'over' becomes 'o' (cricket abbreviation).
'hotel' becomes 'h' (phonetic alphabet: alpha, bravo, charlie etc.).
'ph'+'ara'+'o'+'h'='PHARAOH'
Can you help me to learn more?
(Other definitions for pharaoh that I've seen before include "Eg, Tutankhamen" , "Old Egyptian king" , "Ancient Egyptian ruler" , "Tut, in brief, was one" , "Cheops, for example" .)