What does the cryptic crossword clue "Refrain from TV? Seem agitated in skimpy undies (5,4)" mean?

The wordplay uses an anagram. anagram of EMES (synonym="EMES") + THONG (synonym="‘skimpy undies’") = THEMESONG The answer is THEMESONG.

Refrain from TV? Seem agitated in skimpy undies (5,4)

Guardian Cryptic #29364 | 18 Across | 2024-04-23 flower