The most common and most likely answer to this crossword clue is the 7 letter word NOMINAL
I've seen this crossword clue in The Times
N
O
M
I
N
A
L
More clues leading to the result NOMINAL
- In theory plan I’m only partially up for
- Trivial old bird in northern lake
- Marks in sum docked, after number's very low
- Token loan arranged to enclose most of pit
- Token love-bird found in northern lake
- Small number regularly on call to guard M1
- Very small number — very little, minus one million
- So-called imitator of human speech no linguist initially accepts
- So-called revolutionary plan I monitor a little
- With curtailment in all, “in name only” put another way
Buddy explains!

The straight part
We know that "Trivial" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case trivial = nominal.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does NOMINAL mean?
NOMINAL noun- (grammar) A noun or word group that functions as part of a noun phrase.
- (grammar) A part of speech that shares features with nouns and adjectives. (Depending on the language, it may comprise nouns, adjectives, possibly numerals, pronouns, and participles.)
- A number (usually natural) used like a name; a numeric code or identifier. (See nominal number on Wikipedia.)
- (police jargon) A person listed in the Police National Computer database as having been convicted, cautioned or recently arrested.
- Of, resembling, relating to, or consisting of a name or names.
- Assigned to or bearing a person's name.
- Existing in name only.
- Of or relating to nominalism.
- Insignificantly small.
- Of or relating to the presumed or approximate value, rather than the actual value.
- Of, relating to, or being the amount or face value of a sum of money or a stock certificate, for example, and not the purchasing power or market value.
- Of, relating to, or being the rate of interest or return without adjustment for compounding or inflation.
- (grammar) Of or relating to a noun or word group that functions as a noun.
- According to plan or design.
- Without adjustment to remove the effects of inflation.
- (of a variable) Having values whose order is insignificant.
- Of a species, the species name without consideration of whether it is a junior synonym or in reality consists of more than one biological species.