"Supply and confidence" is an expression used to refer to the arrangement between the party of government and a weaker party, that refers to the fact the weaker

"Supply and confidence" is an expression used to refer to the arrangement between the party of government and a weaker party, that refers to the fact the weaker party will vote with the government on budgets and confidence motions. It doesn't imply a coalition, and the weaker party can't expect ministerial posts.