A friend was having a rant about someone. I did not comment but I did bite my lip - I guess to show sympathy that this person had put my friend in awkward situation. Is this loshon hora on my part ?

Shalom, Thank you for your question. Lashn HaRah is certainly an important, and difficult, command. Let’s examine your situation. Your friend is “having a rant” about someone. This, in all likelihood is lashon ha’rah. Unless the “rant” has a constructive purpose (which doesn’t sound like the situation) it would have been forbidden for your friend to speak the lashon ha’rah in their ranting. When someone is talking lashon ha’rah it is forbidden for others to listen to it. That is, in your case it would have been a sin of lashon ha’rah on your part to listen to forbidden speech. By showing agreement to the forbidden words, it is even worse, as then you also take part in “speaking” the lashon ha’rah. So if you were to nod your head in agreement when someone says “So and so is a real pain in the neck”, then you not only listened to lashon ha’rah, but the nod of agreement strengthened the sin. (It is difficult to know from your question exactly the level of “biting your lip” and whether it shows agreement to the lashon ha’rah or just sympathy to the speaker). However, there is a situation where listening is permitted. That is if your friend really needed to get their anger off their chest, to relieve their pain, in order that they continue their life without inner phycological trauma, then having someone listen to them is permitted. That could be the case you were in – but one should be careful not to stretch this law to far. If though this did apply, then your sympathetic gestures would also be allowed – as they would help calm your friend, and allow them to put their anger aside (which is a mitzvah). Also, if you were listening in order to be able to show them “the other side of the picture” and prove to them that their anger was misplaced, to bring peace to the parties, then it would also be permitted to listen. (See the book “Hafetz Haim”, chapter 6, 4). However, even in such a case, you are not allowed to believe the lashon ha’rah. Nor, of course, are you allowed to add more words of lashon harah. Rather, you could try to lessen the pain of the friend by helping them see that the situation was perhaps not as nasty as they thought, or not premeditated, or directed just against them etc. May we merit to speak and listen to only positive words. Blessings.