Please contribute useful Thai vocabulary words and phrases that you don't often find in dictionaries. I'll add a few of mine:
Ra dup = level ระดับ
Pap ruam = overall ภาพรวม
Bohn = complain บ่น
Soot yawt = highest or best สุดยอด
Sah kah = branch or unit สาขา
Sahmak = apply สมัคร
Gaa punhah = solve the problem แก้ปัญหา