Former US president loses millions, primarily tax dodger (6)
I believe the answer is:
truant
'tax dodger' is the definition.
(thesaurus)
'former us president loses millions primarily' is the wordplay.
'former us president' becomes 'truman' (I've seen this before).
'loses' suggests deleting specific letters.
'millions' becomes 'm' (abbreviation).
'primarily' becomes 't' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'truman' with 'm' taken out is 'truan'.
'truan'+'t'='TRUANT'
Can you help me to learn more?
(Other definitions for truant that I've seen before include "Child who stays away from school without leave" , "Shirker" , "On the mitch" , "'Bunk off'" , "Pupil absent without permission" .)