Lawsuit about uranium sale (7)
I believe the answer is:
auction
'sale' is the definition.
(I've seen this before)
'lawsuit about uranium' is the wordplay.
'lawsuit' becomes 'action' (synonyms).
'about' is an insertion indicator.
'uranium' becomes 'U' (U is the chemical symbol for uranium).
'action' enclosing 'u' is 'AUCTION'.
(Other definitions for auction that I've seen before include "Public bidding sale" , "Competitive sale" , "Offer to bidders" , "Public sale at which bids are made" , "Public sale - type of bridge" .)