Hi Marie! The main difference is in the verbs that can be used with flak and slack. Flak is received; slack is given. Normally, you catch flak and give slack. 1. Catch a lot of flak - means: to get in trouble, to get yelled at or strongly criticized See http://idioms.thefreedictionary.com/get+flak for modern usage See http://public.wsu.edu/~brians/errors/flak.html for original usage Ex. Mike is going to catch a lot of flak for coming home late and breaking his curfew again! 2. Give a lot of slack - means: to give more freedom or tolerance (usually for a behavior or attitude) See http://idioms.thefreedictionary.com/slack Ex: Cut Mike some slack for being out late. It wasn't his fault the car broke down. By the way, I would say "cut (him/her/someone) some slack" rather than "give a lot of slack." 3. This may be a different meaning of flack, which is to publicize or promote something. If so, it is unrelated to the idiom. See http://dictionary.reference.com/browse/flack 4. This is a malapropism. See http://www.mtannoyances.com/?p=526 5. This is incorrect if the idiom is being used. Slack in "give slack" is never plural. Slacks (pants) are something you wear. Maybe this sentence refers to sewing? 6. This is correctly used. She defends other people and leaves herself open to criticism.

1. Catch a lot of flak to be criticized 2. Give a lot of slack to loosen, bend the rules 3. You know, who's going to take up the flack? We really desperately need to have a continuum of marketing efforts. to take up the flack - to be in charge of publicity (advertisement) 6.She does jump in to defend others and leaves herself open to pick up the flak. to pick up the flak - to be criticized, to get blame

5. Can't you just cut me some slacks? Here it means to give additional freedom