certu -cre- gismu

x1 is an expert/pro/has prowess in/is skilled at x2 (event/activity) by standard x3.

Also competent, skilled. See also djuno, stati, kakne.

In notes:

djuno
x1 knows fact(s) x2 (du'u) about subject x3 by epistemology x4.
kakne
x1 is able to do/be/capable of doing/being x2 (event/state) under conditions x3 (event/state).
stati
x1 has a talent/aptitude/innate skill for doing/being x2.
e'e
attitudinal: competence - incompetence/inability.
crejibri
j1=c2 is a profession (job) of person j2=c1.
crekai
x1 does x2 in a skilled manner
creti'i
x1 suggests/offers expert advice/protip x2 (ka) to x3.
jbocre
x1 is an expert in Lojban language.
lacnycre
x1 is an optician
mafcre
c1=m3 is a wizard/sorcerer of m1=c1, which is magical to m2, with standard of sorcery c3.
mencre
c1=m2 (person) is intelligent/smart by standard c3.
nalcre
c1 is lay (non-professional) in event/activity c2 by standard c3.
norcre
x1 is mediocre (in terms of skill) at x2 (ka/activity) by standard x3
rapcreze'a
z1=c1 (experiencer) increases in skill / expertise at z2=c2 by amount z3 by means of repeating action r1 r2 times.
rolrafcre
x1 knows all the rafsi/morphemes of language x2
tolmencre
c1=m2 (person) is unintelligent/dumb/stupid by standard c3.
zmimakfa
x1 is automagic to x2, performed by technology x3.
jo'oi (exp!)
non-logical connective: the more ..., the more...
ertu
x1 is skilled at satisfying property x2, relatively to x3.
ka'elre
x1 learns how to do/be x2 (ka); x1 acquires ability x2 (ka)
ma'estro
x1 is a maestro, musical master in field x2
pamrkovni
x1 is rational, prudent, judicious, level-headed with a limited ken (range of sight)
parcicize
x1 is 1337/leet in aspect/property x2 (ka) by standard x3.
pamniarkovni
x1 is rational, prudent, judicious, level-headed with a limited ken (range of sight)