This phrase is the title of a book by Maidhc Dainín Ó Sé, a writer from Corca Dhuibhne in Kerry.

Would one of the Munster experts be kind enough to explain the phrase and its grammar to me?

Thanks in advance.

Not a Munster expert but taking a crack at it anyway:

Mura mBuafam - Suathfam
"If we don't win, we shall agitate/cause confusion"

Await correction and proper explanation ...

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Múinteoir Gaeilge - Irish Teacher
My "specialty" is Connemara Irish, particularly Cois Fhairrge dialect, but I can also speak Ulster and Munster Irish with native-level pronunciation.
Is fearr Gaeilge ḃriste ná Béarla cliste, cinnte, aċ i ḃfad níos fearr aríst í Gaeilge ḃinn ḃeo na nGaeltaċtaí.
Gaeilge Chonnacht (GC), go háraid Gaeilge Chois Fhairrge (GCF), Gaeilic Uladh (GU), Gaelainn na Mumhan (GM), agus Gaeilge an Chaighdeáin Oifigiúil (CO).

Breandán is spot on! the termination "fam" is the 1st person plural of the Future tense in Munster, especially in the Cork Gaeltacht (it was a form especially favoured by Amhlaoibh Ó Loingsigh, Múscraíoch and one of the finest seanachaithe and scéalaithe of our time). The "Fam" termination is interchangeable with the regular "aimíd" ending also.

The termination itself, stems from the conjunct/ dependent form, of the 1st person plural of the simple future tense verbs:

Absolute

marbfimmi (we will kill)

Conjunct

Ní marbfam (we will not kill)

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Please wait for corrections/ more input from other forum members before acting on advice

Ah so it's a survival from Old Irish.
I thought it might be the first person plural future but wondered if it was just a contraction of -aimíd or if it had another derivation.
Thanks to ye both for taking the time to answer me.