Two words            
May be 2 words combined (certavis+simus) If not obvious, probably incorrect
vis                  TACKON                             
TACKON (what)-ever (w/quantus) [quantusvis => of whatever size you like];
cert.a               ADJ    1 1 NOM S F POS             
cert.a               ADJ    1 1 VOC S F POS             
cert.a               ADJ    1 1 ABL S F POS             
cert.a               ADJ    1 1 NOM P N POS             
cert.a               ADJ    1 1 VOC P N POS             
cert.a               ADJ    1 1 ACC P N POS             
certus, certa -um, certior -or -us, certissimus -a -um  ADJ   [XXXAO]  
fixed, settled, firm; certain; trusty/reliable; sure; resolved, determined;
sim.us               ADJ    1 1 NOM S M POS             
simus, sima, simum  ADJ   [XBXCO]  
flatnosed, snub-nosed; having flattened nose; flatten/splayed (nose/other);
s.imus               V      5 1 PRES ACTIVE  SUB 1 P    
sum, esse, fui, futurus  V   [XXXAX]  
be; exist; (also used to form verb perfect passive tenses) with NOM PERF PPL
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