How do you say spear in Chinese?
— 矛; 矛

Generic synonyms for spear in Chinese
arm胳膊 (gēbo), 胳臂 (gēbei), 手臂 (shǒubì), 臂膀 (bìbǎng)
weapon武器 (wǔqì), 兵器 (bīngqì)