Substitute Posted on 22nd December 20156th May 2021 by ThePD (The Project Definition) Substitute is to use something or someone instead of another thing or person. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in General and tagged word. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.