Well, could be one guy primarily with escort (6)
I believe the answer is:
gusher
'well' is the definition.
(I know that gusher is a type of oil well)
'one guy primarily with escort' is the wordplay.
'primarily' suggests taking the first letters.
'with escort' becomes 'usher' (usher is a kind of escort. I am not sure about the 'with' bit.).
The first letter of 'guy' is 'g'.
'g'+'usher'='GUSHER'
'could be' is the link.
Can you help me to learn more?
(Other definitions for gusher that I've seen before include "Effusive person or oil well in action" , "effusive type" , "one's over-effusive" , "Oil-well with a strong natural flow" , "An active oil well or excessive talker" .)