In the past they have been used with each other's meanings, but these senses have now fallen out of use.

An example from a letter of George Washington to Alexander Spotswood (24 September 1798):

I shall depend upon your Overseer, Roger Farril, for my Mansion house concern; and Brookes Joiner, to overlook my Carpenters.

Scanning through the rest of the letters, he seems to use "overlook" for "oversee" fairly often - even, as here, in the same letter.

And for the reverse, from the play The Way of the World by William Congreve (1700):

'Twas for my ease to oversee and wilfully neglect the gross advances made him by my wife, that by permitting her to be engaged, I might continue unsuspected in my pleasures, and take you oftener to my arms in full security.

Neither of these senses are current in English any more.

In the past they have been used with each other's meanings, but these senses have now fallen out of use. Just part of the way language changes - they used to overlap more, but now they don't, and there may not be any particular reason why.

An example from a letter of George Washington to Alexander Spotswood (24 September 1798):

I shall depend upon your Overseer, Roger Farril, for my Mansion house concern; and Brookes Joiner, to overlook my Carpenters.

Scanning through the rest of the letters, he seems to use "overlook" for "oversee" fairly often - even, as here, in the same letter.

And for the reverse, from the play The Way of the World by William Congreve (1700):

'Twas for my ease to oversee and wilfully neglect the gross advances made him by my wife, that by permitting her to be engaged, I might continue unsuspected in my pleasures, and take you oftener to my arms in full security.

Neither of these senses are current in English any more.

In the past they have been used with each other's meanings. An example from a letter of George Washington to Alexander Spotswood (24 September 1798):

I shall depend upon your Overseer, Roger Farril, for my Mansion house concern; and Brookes Joiner, to overlook my Carpenters.

Scanning through the rest of the letters, he seems to use "overlook" for "oversee" fairly often - even, as here, in the same letter.

And for the reverse, from the play The Way of the World by William Congreve (1700):

'Twas for my ease to oversee and wilfully neglect the gross advances made him by my wife, that by permitting her to be engaged, I might continue unsuspected in my pleasures, and take you oftener to my arms in full security.

Neither of these senses are current in English any more.

In the past they have been used with each other's meanings, but these senses have now fallen out of use. 

An example from a letter of George Washington to Alexander Spotswood (24 September 1798):

I shall depend upon your Overseer, Roger Farril, for my Mansion house concern; and Brookes Joiner, to overlook my Carpenters.

Scanning through the rest of the letters, he seems to use "overlook" for "oversee" fairly often - even, as here, in the same letter.

And for the reverse, from the play The Way of the World by William Congreve (1700):

'Twas for my ease to oversee and wilfully neglect the gross advances made him by my wife, that by permitting her to be engaged, I might continue unsuspected in my pleasures, and take you oftener to my arms in full security.

Neither of these senses are current in English any more.