horse-trading
noun [ U ] often disapproving uk/ˈhɔːsˌtreɪ.dɪŋ/ us/ˈhɔːrsˌtreɪ.dɪŋ/
（私下里进行的对双方都有好处的）讨价还价
unofficial discussion in which people make agreements that provide both sides with advantages
There's been a lot of political horse-trading while the parties try to form a government. 那些政党在组建政府期间私下里进行了多次讨价还价。