介添え[kaizoe] helper
寄添う[yorisou] to get close
後添い[nochizoi] one's second wife
食品添加物[shokuhintenkabutsu] food additive
申し添える[moushisoeru] to add to what has been said

添う[sou] to meet (one's expectations, etc.)
添加[tenka] addition
添加剤[tenkazai] addition agent
添加物[tenkabutsu] addition
添削[tensaku] correction

奥附[okuzuke] colophon
先附[sakizuke] appetizer
添附[tenpu] attachment (e.g. email)
日附[hizuke] date
番附[banzuke] ranked list (entertainers, sumo wrestlers, millionaires, etc.)

附する[fusuru] to affix
附ける[tsukeru] to attach
附加える[tsukekuwaeru] to add one thing to another
附根[tsukene] root
附け狙う[tsukenerau] to prowl after