項 and 工 don't sound similar in modern Mandarin due to historical phonetic changes. They were more similar in older Chinese.項 /*[g]ˤroŋʔ/ 工 /*kˤoŋ/, /*kˤoŋ/
neck, nape of neck; sum; funds; back of neck; item; thing; term (in a mathematical formula); sum (of money); classifier for principles, items, clauses, tasks, research projects etc
