Synthesis reaction: endothermic or exothermic?

Endothermic is a process where heart or energy is taken from somewhere to do a certain process (e.g cooking). Exothermic is the opposite, whereby energy or heat is taken out from a certain process to somewhere (e.g exercising). Synthesis is the building up of something using available resources(e.g Heat), so synthesis, i will say is endothermic because heart will be taken from somewhere to build up something(e.g Cooking) .