Border straddled by distinguished gentlemen (4)
I believe the answer is:
edge
'border' is the definition.
(synonyms)
'straddled by distinguished gentlemen' is the wordplay.
'straddled by' indicates the answer is hidden within the clue (the clue straddles both sides of the solution).
'EDGE' is hidden in the letters of 'distinguished gentlemen'.
(Other definitions for edge that I've seen before include "Rim,border" , "marginal advantage" , "Sharp ridge" , "'Border, boundary, rim (4)'" , "Outer limit" .)