thick as thieves
adjEtymology From thick (“friendly, intimate”), first attested in 1827 as "thick as two thieves".
1
Idiomatic Intimate, close-knit, tight.
Of friends or members of a group
- So the king sneaked into the wigwam and took to his bottle for comfort, and before long the duke tackled HIS bottle; and so in about a half an hour they was as thick as thieves again, and the tighter they got the lovinger they got, and went off a-snoring in each other's arms.1884, Mark Twain, chapter 30, in Huckleberry Finn:
- He and Victoria were as thick as thieves, and are about equal in wickedness.1904, Fergus Hume, chapter 9, in The Red Window:
1 more example
- President Bush may think he's as thick as thieves with his pal Vladimir Putin, but hopefully someone at the White House is reading the English edition of Pravda.2001 October 26, Tony Karon, “What They're Saying About the War”, in Time, retrieved 04 Aug 2015: