In cases of complicated words, you need to remember that English evolved from several other languages, especially Latin and Greek.
If you know one word, it can lead you to knowing many more related words with the same letters at the beginning (prefix), in the middle (infix) or at the end (suffix).
Look at these words and see if they carry some similar sense: abnormal, absent, absolutely, abduct, abdicate, abort, absorb, abrasive and aberrant.
The prefix ab- or abs- is a Latin origin which means ‘away’, ‘from’ or ‘separation’. This means there is a sense of ‘being away’ in most of the words that begin with ab or abs.
Even before we examine many words for your information, if you know what the word absent means, you can easily know the meaning of abnormal, absorb, and etcetera.
By the guidance of ab meaning, the word abnormal directly means ‘away from being normal’ or the opposite of normal.
You can see that it is close to the current meaning of ‘not being up to the standard or not typical.
Originally , the word absent was used to mean being ‘away from where a student or representor had been sent’ which is close to the current mean of being away from any place or occasion.
At this stage, you can easily know that ‘abduct’ has two words: ab and duct. If ab means away and duct means passageway, the word literally mean away from the passageway or the intended course/ direction which is close to the current meaning of ‘kidnap’.
Although some English learners have found the meaning of the word absolute difficult to relate to the sense of ‘being away’, the word is typical in the line of all other words with ab.
When you are absolutely sure about something, you are loosened ‘away’ from all doubt which is close to the current meaning of certainly, definitely or totally.
Consider other such as abort which means ‘away’ from rising or beginning; absorb which means suck ‘away’; aberration which is an act of wandering away; abolish which means to do ‘away’ with and abstain which means holding off ‘from’ something.