Almost board ship prior to travel ban (7)
I believe the answer is:
embargo
'ban' is the definition.
(thesaurus)
'almost board ship prior to travel' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'board ship' becomes 'embark' (I've seen this before).
'prior to' says to put letters next to each other.
'travel' becomes 'go' ('go' can be a synonym of 'travel').
'embark' with its last letter taken away is 'embar'.
'embar'+'go'='EMBARGO'
(Other definitions for embargo that I've seen before include "Order intended to prevent trade" , "Ban or restraint on trade" , "Trade sanction" , "restrict trade" , "Legal stoppage of commerce" .)