To forswear is to swear falsely. As nouns the difference between promise and swear is that promise is an oath or affirmation; a vow while swear is a swearword. Let me try to give you a simple explanation of the difference. Guarantee is usually used to refer to future events, though not exclusively. Oath, while close in meaning, typically has an additional sense of invoking the divine (e.g., an oath taken on the bible).

A verb with close meaning to all three is to swear. ), that someone will do some particular thing--like speak the truth, perform a particular act, keep a promise, etc. As a adjective swear is heavy. All of these are based on my American English background and usage.

To swear is to make the oath. An oath is a declaration made to man (or men) with God as witness, whereas a vow is a promise made to God alone, optionally with men as witnesses. Swearing sometimes bears a religious or legal connotation, and assure is generally taken to be a more formal synonym for promise. They mean “a solemn promise” (this is NOAD's main definition for both). What about a covenant? Now I’ve touched on this before, but there is a distinct and important difference between a “vow” and an “oath“.

In that sense, a vow is a promise made to God. As verbs the difference between promise and swear is that promise is to commit to something or action; to make an oath; make a vow while swear is to take an oath or swear can be to be lazy; rest for a short while during working hours. A vow is basically a conditional promise and is usually phrased like this: As a adjective swear is heavy. As verbs the difference between vow and swear is that vow is (ambitransitive) to make a vow; to promise while swear is to take an oath or swear can be to be lazy; rest for a short while during working hours.