the ick

 It is clear that ick comes from icky but at this point the Oxford English Dictionary throws up its hands in helplessness and says ‘origin uncertain’.  However, the example sentences show that icky was a word of the jazz scene in America in the 1930s and described music that was over-sweet and sentimental, music that a true lover of swing jazz despised.  The suggestion is that icky was pretend baby talk meaning ‘little’. 

 From bad music icky progressed to cover anything that was disgusting, that produced a slight recoil and a wrinkled nose.  Icky-boo meant ‘ill’.  James Joyce seems to have taken it to an extreme with ickylickysticky.  They blow ickylickysticky yumyum kisses. (Ulysses 1922).

 The shortened form ick meant much the same but could be used as an exclamation of revulsion.  In the 1970s we arrived at the ick factor, the particular quality of something or someone that you regard as ick. Sex and the City had an episode titled The Ick Factor which dealt with a relationship threatened by an overdose of romance .
More recently in discussions on social media the ick factor has been shortened to the ick. It seems that what seems to be perfect love can suddenly by brought down by the ick.  This can be an habitual turn of phrase that drives you crazy, a sound such as a laugh or a snort or a cough,  a terrible clothes sense or a love of music that you find hideous.  Instantaneously, the whole thing is off.  The advice is to look more closely to see if the revulsion is your defence mechanism springing into action because you are afraid of intimacy, or if the supposed ick is really something trivial that you have blown up into a major drama.  Perhaps you really just don’t like the proposed partner any more so heed the ick and move on.