A tantalising person relaxed (2,4)
I believe the answer is:
at ease
'relaxed' is the definition.
(similar in meaning)
'a tantalising person' is the wordplay.
'tantalising person' becomes 'tease' (I can't explain this - if you can you should give a lot more credence to this answer).
'a'+'tease'='AT EASE'
Can you help me to learn more?
(Other definitions for at ease that I've seen before include "Calm" , "In a relaxed attitude" , "Free from discomfort - that's an order" , "unworried" , "Relaxing - that's a military order" .)