Tangible diplomacy is lies, oddly (7)
I believe the answer is:
'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).
The alternate letters of 'islies' are 'ile'.
(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" .)