Line that woman takes in was knotted (6)
I believe the answer is:
hawser
'line' is the definition.
(hawser is a kind of line)
'woman takes in was knotted' is the wordplay.
'woman' becomes 'her' (**).
'takes in' means one lot of letters goes inside another.
'knotted' indicates anagramming the letters.
'was' anagrammed gives 'aws'.
'her' placed around 'aws' is 'HAWSER'.
'that' is the link.
(Other definitions for hawser that I've seen before include "Heavy rope used at sea" , "Large heavy rope" , "Ship's mooring rope" , "Heavy cable for securing ships" , "Ship's tow-rope" .)