What does the cryptic crossword clue "U.S. embassies not designed for being restrained (14)" mean?

The wordplay uses an anagram. anagram of U.S. + EMBASSIES + NOT = ABSTEMIOUSNESS The answer is ABSTEMIOUSNESS.

U.S. embassies not designed for being restrained (14)

Daily Mail Cryptic #17397 | 8 Down | 2024-07-09 flower