Desert son in big way? (5)
I believe the answer is:
sinai
'desert' is the definition.
(I know that Sinai is a desert)
'son in big way?' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'big way?' becomes 'ai' (I can't explain this - if you can you should give a lot more credence to this answer).
's'+'in'+'ai'='SINAI'
Can you help me to learn more?
(Other definitions for sinai that I've seen before include "place to receive instructions about behaviour" , "Peninsula, mostly desert, at north end of Red Sea" , "Biblical mount" , "One showing genetic change" , "Deserted area" .)