Don’t bare your teeth until you can bite.
Note: There is another variation to this week’s proverb. “Ná taispeáin d’fhiacail san áit nach dtig leat greim a bhaint amach.” (Don’t show your teeth where cannot give a bite. Literally: Don’t show your teeth in a place you may not be able to take a bite out.) In Scots Gaelic, there is a slight variation. “Mur comas dut teumadh, na rùisg do dheudach.” (If you cannot bite, don’t show your teeth.) Sun Tzu knew this in 500 B.C. “He who knows when he can fight and when he cannot will be victorious.” — Sun Tzu, The Art of War, III, 25.
Note also: In the two Irish versions of this week’s proverb, there are two different plural forms of the word ‘fiacail,’ namely ‘fiacla’ and ‘fiacail.’ The first is the official standard plural, ‘fiacla.’ You will see this standard in the Chois Fharraige dialect in county Galway. In parts of Donegal, you will see the non-standard plural, ‘fiacail.’ In these non-standard cases, the nominative sinular form is ‘fiacal,’ not ‘fiacail.’ This is not to say that Galway speakers always use the official standard. Such is not the case. In fact, nobody speaks the official standard. The official standard is a standard for spelling and grammar, not pronunciation. A standard pronounciation was proposed later called ‘an Lárchanúint’ (the core dialect), ach sin scéal eile.