What does the cryptic crossword clue "These could be silly so-and-sos without intelligence (7)" mean?

The wordplay uses a container (one word inside another). WIT (synonym="intelligence") in NITS (synonym="NITS") = NITWITS The answer is NITWITS.

These could be silly so-and-sos without intelligence (7)

Guardian Cryptic #29247 | 18 Down | 2023-12-07 flower