The lady's bringing in gold left with international trucker (7)
'trucker' is the definition.
(I've seen this before)
'the lady's bringing in gold left with international' is the wordplay.
'the lady' becomes 'her' (I've seen this before).
'bringing in' indicates putting letters inside.
'gold' becomes 'Au' (Au is the chemical symbol for gold).
'left with' becomes 'l' (common abbreviation. I am not sure about the 'with' bit.).
'international' becomes 'i' (abbreviation eg in IMF).
'her' enclosing 'auli' is 'HAULIER'.
Can you help me to learn more?
(Other definitions for haulier that I've seen before include "freight carrier", "Commercial transporter", "Transporter of goods by road", "Transport contractor", "One transports goods in a vehicle".)