rudimentary
adj
1 existing in an imperfect or undeveloped form 未充分發展的; 發育不成熟的; 退化的
Some breeds of dog have only rudimentary tails. 有些品種的狗尾巴只有退化的部分.
2 (derog 貶) elementary; (not more than) basic 初步的; (充其量)基本的
I have only a rudimentary grasp of physics. 我對物理學僅有初步的了解.