Tense difficult, might you say? (6)
I believe the answer is:
uneasy
I believe this clue is a double definition.
'tense' is the first definition.
(similar in meaning)
'difficult might you say?' is the second definition.
(un-easy, not easy - imaginative interpretation)
(Other definitions for uneasy that I've seen before include "Anxious, nervous" , "Shakespeare: '. . . . . lies the head that wears a crown'" , "Anxious, unquiet" , "Disturbed" , "Awkward" .)