Tangible diplomacy is lies, oddly (7)
I believe the answer is:
tactile
'tangible' is the definition.
(similar in meaning)
'diplomacy is lies oddly' is the wordplay.
'diplomacy' becomes 'tact' (tact can mean diplomacy or sensitivity).
'oddly' indicates alternate letters (letters in the odd-numbered positions are used).
'is'+'lies'='islies'
The alternate letters of 'islies' are 'ile'.
'tact'+'ile'='TACTILE'
(Other definitions for tactile that I've seen before include "Tangible - of touch" , "Cattle I find with sense of touch" , "Touchy-feely" , "Likely to touch" , "Lattice being sensitive to touch" .)