More difficult to pull in lace underwear ultimately (8)
I believe the answer is:
trickier
'more difficult' is the definition.
('tricky' can be similar in meaning to 'difficult')
'pull in lace underwear ultimately' is the wordplay.
'pull' becomes 'rick' (I can't justify this - if you can you should give a lot more credence to this answer).
'in' is an insertion indicator.
'lace' becomes 'tie' (I've seen this in another clue).
'ultimately' says to take the final letters.
The last letter of 'underwear' is 'r'.
'rick' put within 'tie' is 'trickie'.
'trickie'+'r'='TRICKIER'
'to' acts as a link.
Can you help me to learn more?
(Another definition for trickier that I've seen is " More complicated".)