(military, also figurative) A soldier involved in the design and construction of military or other engineering works.

(by extension) A person professionally engaged in the technical design, construction, and maintenance of large-scale structures and machinery, or someone who uses their abilities to manipulate events or people.

(transitive) Employ one's abilities and knowledge to design, construct, and/or maintain something, use genetic engineering to alter or construct a dna sequence or organism, and plan or achieve a goal through contrivance or guile.

(intransitive) Formulate plots or schemes, plot, scheme, and work as an engineer.