• apratyutthāyinam — not rising in greeting
  A- + prati-ut-thāyin (one who rises in response). Vedic protocol: rise when a guru, sannyāsī, or Vaiṣṇava enters. Romaharṣaṇa's failure is registered grammatically as a privative — what should have been, wasn't.
• sūtam — the sūta (a mixed-caste bard)
  Sūta = offspring of a kṣatriya father and brāhmaṇa mother (pratiloma). Traditionally the chronicler caste. The term is descriptive, not pejorative — but combined with his posture it marks a categorical breach of seating-order.
• akṛta-prahvaṇa-añjalim — having made neither bow nor folded palms
  A- (not) + kṛta (done) + prahvaṇa (bowing) + añjali (folded palms). Three protocols compressed into one negative compound. The grammar enacts the offense — refusal made into a single word.
• adhyāsīnam — sitting above
  Adhi- (above) + āsīna (seated). Above the brāhmaṇas. Vedic seating-order assigns the highest seat to the senior brāhmaṇa or to the Lord; the breach is geometric as well as social.
• cukopa — became angry
  Perfect of √kup. Note: Balarāma is rohiṇī-tanaya, the embodiment of dhairya, slow to anger. When He cukopa, the breach was real. Gauḍīyas read His krodha as an aspect of His protection of dharma.

• Where do I treat protocol toward holy persons as if it didn't matter?
• What act of standing, bowing, or palms-joined would reset something?

Three omissions in one posture — Romaharṣaṇa did not stand, did not bow, did not join palms — and he sat above brāhmaṇas. The breach is layered, like a chord. Balarāma's anger is not at one wrong note; it is at the chord struck on the seat of the spiritual teacher.