Institutionalized phrases are conventionalizedทำให้เป็นธรรมเนียม phrases, such as salt and pepper, traffic light and to kindle excitementความตื่นเต้น. They are semantically and syntactically compositional, but statistically idiosyncratic. Regarding the phrase traffic light, traffic and light both retain simpex senses but produce a compositional reading by combining constructionally.
semantically
excitement