fasnu -fau- gismu

x1 (event) is an event that happens/occurs/takes place; x1 is an incident/happening/occurrence.

(cf. cmavo list fau, krefu, lifri, fatci, rapli; gasnu, zukte, if specifically agentive, banli)

In definition:

fau
fasnu modal, 1st place (non-causal) in the event of ...

In notes:

banli
x1 is great/grand in property x2 (ka) by standard x3.
fatci
x1 (du'u) is a fact/reality/truth/actuality, in the absolute.
gasnu
x1 [person/agent] is an agentive cause of event x2; x1 does/brings about x2.
krefu
x1 (event) is the x3'rd recurrence/repetition of x2 (abstract); x2 happens again in [form] x1.
lifri
x1 [person/passive/state] undergoes/experiences x2 (event/experience); x2 happens to x1.
zukte
x1 is a volitional entity employing means/taking action x2 for purpose/goal x3/to end x3.
cabyfau
c1=f1 is live (experienced as it happens) to experiencer c2.
cazyfau
f1 is actual (existing in act or reality, not just potentially).
fasnyvla
v1 is a verb meaning v2 in language v3.
faurtei
f1 is an event that has time/temporal duration t1 ranging from starting time/event t2 to ending time/event t3.
datru
x1 (event) is dated/pertaining to day/occurring on day x2 of month x3 of year x4 in calendar x5