استح من ذم من لو كان حاضرا لبالغت في مدحه, و مدح من لو كان غائبا لسارعت الى ذمه It's a proverb that means "Don't speak about people behind their backs" i.e. the proverb is especially intended for hypocrites. I tried to correct it so that it would make more sense. Its literal translation will be separately as follows: 1- استح من ذم من لو كان حاضرا لبالغت في مدحه Don't dispraise him, whom you would have praised in presence. 2- و مدح من لو كان غائبا لسارعت الى ذمه And don't praise him, whom you would have dispraised in absence. I wish it could help...

كان حاضرا not كانحاضرا They are 2 words not one: كان was حاضرا present

feel/be ashamed to dispraise someone who if present, you will praise excessively/ exaggerate in praise; and to praise who if abesnt you will rush to dispraise.