Stretch script with no beginning and finish (6)
I believe the answer is:
extend
'stretch' is the definition.
(synonyms)
'script with no beginning and finish' is the wordplay.
'script' becomes 'text' (I've seen this before).
'with no beginning' means to remove the first letter.
'and' says to put letters next to each other.
'finish' becomes 'end' (synonyms).
'text' with its first letter taken away is 'ext'.
'ext'+'end'='EXTEND'
(Other definitions for extend that I've seen before include "Enlarge, widen" , "Straighten out" , "Spread - offer" , "Reach out or stretch" , "Provide challenge" .)