Transport similar to mass gathering? (6)
I believe the answer is:
ravish
'transport' is the definition.
(synonyms)
'similar to mass gathering?' is the wordplay.
I cannot really see how this works, but
'similar' could be 'ish' (similar in meaning) and 'ish' is located in the answer.
This explanation may well be incorrect...
(Other definitions for ravish that I've seen before include "entrance" , "Enchant" , "Transport with delight" , "Rape" , "Seize and carry off" .)