Qui amicum fallit, amicitiam laedit.

Here qui means the one who, he who, or more generally whoever.

So the sentence is not just about one specific man. It states a general truth:

• Qui amicum fallit = the person who deceives a friend
• amicitiam laedit = harms friendship

In grammatical terms, qui is a relative pronoun, but here it is being used on its own without an expressed noun before it.

Because qui is the subject of the verbs fallit and laedit.

• qui = the one who does the action
• amicum = the friend who is deceived
• amicitiam = friendship, which is harmed

If Latin used quem, that would mean whom, which would make it an object, not the subject.

So:

• qui fallit = who deceives
• not quem fallit = whom he deceives

Yes. Latin often leaves it unstated.

You can think of an implied idea like:

• is qui = the one who
• or simply someone who

But Latin very naturally uses qui by itself in this kind of general statement. English sometimes does something similar with whoever or he who.

Because they belong to different declensions.

Both words are in the accusative singular, because both are direct objects:

• amicum is the object of fallit
• amicitiam is the object of laedit

But their dictionary forms are different:

• amicus, amici = friend → accusative singular amicum
• amicitia, amicitiae = friendship → accusative singular amicitiam

So the different endings do not mean different jobs here. They both mark the direct object, but each noun declines according to its own pattern.

Because fallere takes a direct object in Latin.

So:

• amicum fallit = he deceives a friend

Latin does not say this as he deceives to a friend or he deceives for a friend. The friend is the person directly affected by the action, so Latin uses the accusative.

Both are:

• 3rd person singular
• present tense
• active voice
• indicative mood

More specifically:

• fallit = deceives
• laedit = harms / injures

They are singular because the subject qui is understood as the one who or whoever—a singular idea.

Because this sentence expresses a general truth or moral principle.

Latin often uses the present tense for statements like this:

• Qui amicum fallit, amicitiam laedit.
• Whoever deceives a friend harms friendship.

This is not necessarily describing something happening right now. It is stating what is generally true.

It has two parts:

1. Qui amicum fallit = a relative clause
2. amicitiam laedit = the main clause

The same subject, qui, is understood for both verbs.

So the logic is:

• the person who deceives a friend
• harms friendship

A helpful way to see it is:

• Qui ... fallit = Whoever ... deceives
• [is] amicitiam laedit = ... harms friendship

Latin does not need to repeat the subject.

Yes. Latin word order is more flexible than English because the endings show each word’s role.

This sentence could appear in other orders, for example:

• Amicitiam laedit qui amicum fallit.
• Qui fallit amicum, laedit amicitiam.

Those still mean essentially the same thing.

The given order is neat and balanced:

• amicum fallit
• amicitiam laedit

That parallel structure makes the statement sound pointed and memorable.

No. laedere can mean to harm, injure, damage, or wound, and it can be used in both physical and non-physical senses.

Here it is used with an abstract noun:

• amicitiam laedit = harms friendship

So the idea is not that friendship is physically hurt, but that the bond or relationship is damaged.

They refer to two related but different things:

• amicum = a friend, the person
• amicitiam = friendship, the relationship

That is what gives the sentence its force. It says that betraying the person also damages the relationship itself.

So the thought moves from:

• the individual friend to
• friendship as a value or bond

This is why the sentence feels like a moral maxim.