1.
without doubt (used for emphasis). Inner side of a person, object or thing
certainly
surely
for sure
unquestionably
without/beyond doubt
without/beyond question
beyond any doubt
undoubtedly
indubitably assuredly
positively
absolutely in a definite manner; clearly.
inner side of something.
interior
inner part
2.
the inner part; the interior.
situated in, or derived from, the inside.
inner
interior
internal
inmost
innermost
"Sir, we found something that is going to spread and become infinite."
"Well do we know how long this is going to occur?"
"No sir, it is indefinitely infinite."