The first member of a tat-puruṣa samāsa preserves its original accent when it ends in pati and means 'master' or 'lord'.,
Thus गृह꣡पतिः, से꣡नापतिः, न꣡रपतिः, धान्य॑पतिः ॥ The word गृह is formed by क (III. I. 144) and has acute on the final (III. I. 3). The word सेना is a Bahuvrihi (सह इनेन वर्तते = से꣡ना), and by (VI. 2. I) the first member retains its accent. The word नर is derived from नॄ 'to lead' by the affix अप् 3.3.57 and has acute on the first (III. I. 4), the word धान्य॑ has svarita on the final (See Phit II. 23?) Why do we say when meaning 'lord'? Observe ब्राह्मणो वृषलीपतिः꣡ \a Brahmana, husband of a Sudra\.,