precipitant

(noun) an agent that causes a precipitate to form.

(adj) done with very great haste and without due deliberation. Synonyms: hasty, overhasty, precipitate, precipitous. Examples: "Hasty marriage seldom proveth well"- shakespeare." "Hasty makeshifts take the place of planning"- arthur geddes." "Rejected what was regarded as an overhasty plan for reconversion." "Wondered whether they had been rather precipitate in deposing the king."