Synonyms of the word

vestigial

• adj. Of or pertaining to a vestige or remnant; like a trace from the past.
• adj. Not fully developed in mature animals.
• n. (biology) A small, degenerate, or imperfectly developed part or organ which has been more fully developed…

rudimentary

• adj. Of or relating to one or more rudiments.
• adj. Basic; minimal; with less than, or only the minimum, necessary.
• n. (zoology, usually in the plural) One of the rudimentary mammae of boars.

undeveloped

• adj. not developed or used.
• adj. not built on, unbuilt; not ready for building on.
• adj. lagging behind others, especially in economic or social matters.