jar (SHAKE)phoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic verb 

1. to shake or influence unpleasantly, or to cause unpleasant feelings 

   The train stopped suddenly, jarring me against the door. [T]
    A screech of brakes jarred the silence. [T]
    The harsh colours jarred the eye (=were unpleasant to look at). [T]
    His rather superior manner jars on me. [I]

2. To jar with is to disagree with, or not to match or fit suitably. 

   This comment jars with the opinions we have heard expressed elsewhere.

jar phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic noun [C] 

   The tram started to move off with a jar (=sudden unpleasant shake).

jarring phoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticPhoneticphonetic adjective 

1. Something which is jarring causes unpleasant feelings, esp. because it does not match or fit suitably 
    with other things. 

   a jarring cry
    jarring colours
    jarring points of view
    a jarring experience

This page is cited from Cambridge Dictionaries Online.  For the original, please visit
http://dictionary.cambridge.org/define.asp?key=jar*2+0