Meaning: a susceptible or vulnerable area.

Example:
She is a brilliant social worker but her lack of political awareness may be the chink in her armour.

Meaning: good for, congratulations to, hurrah for.

Example:
1.- Three cheers for Liverpool Football Club for great victory of Grand Final match.
2.- Three cheers for your beautiful, newly born baby.

Meaning: one has to make adequate provision for their family before one make provision for needy strangers.

Example:
She spends the little money that she earns on social work and neglect her own family, forgetting that charity begins at home.

Meaning: to take a decision without caring about the negative effects that come with it. To not worry about the ill effects of doing something.

Example:
1.- The caretaker threw caution to the winds when taking the baby out of the house even though he was already sick.
2.- She throws caution to the winds every time she goes shopping. Her purchases are always among the most expensive and her husband keeps trying his best to pay the bills off later.